Post on 09-Feb-2019
The Second International Workshop for Far East Asian Young Rheologists
January 26-28 2007 Kyoto Institute of Technology Matsugasaki Sakyo-ku Kyoto 606-8585 JAPAN
ProgramTable of Contents20071261100 minus Registration1300 -1310 Opening Remarks
Session I (Chairman H Watanabe (ICR Kyoto Univ) )page
1310 -1335 Rheological properties of novel silk fiberpoly (ε-caprolactone) biocomposites
Wei Li (Shanghai Jiao Tong Univ) 11335 -1400
Rheological characterization of hydrogel formed by the blend of silk fibroin andhydroxypropylcellulose
Zuguang GONG (Fudan Univ) 2
1400 -1415Relation between electric charges and beads formation on Electro-spinning ofPoly(vinyl alcohol)
Yosuke KADOMAE (Yamagata Univ) 3
Session II (Chairman Z Z Shao (Fudan Univ) )1415 -1430
Sensitivity of Low- and High-speed Spinning Process with Flow-InducedCrystallization Kinetics
Jang Ho Yun (Korea Univ) 4
1430 -1445Predicting permeability for fibrous porous media based on micro-structure with directsimulation method
Jun Feng Wang (Gyeongsang Natl Univ) 5
1445 -1500The effect of viscosity and flow rate on the droplet size and formation pattern in T-shaped microchannel
Duwon Choi (Seoul Natl Univ) 6
1500 -1520 Coffee BreakSession III (Chairman W R Hwang (Gyeongsang Natl Univ) )
1520 -1545 Transient behaviors of immiscible polymer blends under varying flow field
Quan Chen (Shanghai Jiao Tong Univ) 7
1545 -1600The effect of viscosity and elasticity on the DOD (Drop-On-Demand) inkjet dropformation
A Young Lee (Seoul Natl Univ) 8
1600 -1625 Viscoelastic Properties of polyisoprenepoly(t-butyl styrene) blends
Jun Takada (Kyoto Univ) 9
1625 -1830 Poster Session1830 -2000 Reception
2007127Session IV (Chairman YD Kwon (Sungkyunkwan Univ) )
page
930 -955 Normal stress development under large amplitude oscillatory shear flow
Jung Gun Nam (Seoul Natl Univ) 10
955 -1010Nonlinear behavior of complex fluids under large amplitude oscillatory shear andsqueezing flow
Juha Hwang (Seoul Natl Univ) 11
1010 -1025 Studies on micro-convections induced in a polymer solution heated from above
Yasuhiro YAMADA (Kyoto Inst Technol) 12
Session V (Chairman K Sun (Shanghai Jiao Tong Univ) )1025 -1040 Development of a mixed-flow rheometer
Jae Hee Kim (Seoul Natl Univ) 13
1040 -1105 Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA (Yamagata Univ) 14
1105 -1130 Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim (Seoul Natl Univ) 15
1130 -1150 Coffee BreakSession VI (Chairman K H Ahn (Seoul Natl Univ) )
1150 -1215 The Effect of Shear Flow on the Reaction of POE with Peroxide
Jianye Liu (Shanghai Jiao Tong Univ) 16
1215 -1230Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient ShearFlow ----
Hideyuki UEMATSU (Yamagata Univ) 17
1230 -1245Investigation of polyethylene coupling reaction initiated by Dicumyl peroxideoccurred in Haake internal mixer using two-dimensional numerical simulation method
Ji Zhou (Shanghai Jiao Tong Univ) 18
1245 -1340 Lunch1340 -1800 Free Discussion1800 -2000 Dinner
2007128Session VII (Chairman W Yu (Shanghai Jiao Tong Univ) )
930 -945 Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki Sato (Tokyo Univ of A amp T) 19
945 -1010A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles and their surfacecoating
Ke Tao (Shanghai Jiao Tong Univ) 20
1010 -1025 Particle Tracking in a drying process
So Youn Kim (Seoul Natl Univ) 21
Session VIII (Chairman Y Masubuchi (Tokyo Univ of A amp T) )page
1025 -1050Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong (Kyoto Inst Technol) 22
1050 -1115 Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin (Korea Univ) 23
1115 -1130Measuring viscoelastic behavior of dilute suspensions with particle trackingmicrorheology
Heekyoung Kang (Seoul Natl Univ) 24
1130 -1150 Coffee BreakSession IX (Chairman S Sakurai (Kyoto Inst Technol) )
1150 -1215 Stress development in suspension coating process
Sunhyung Kim (Seoul Natl Univ) 25
1215 -1230Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in SteelProducts
Hak-Yul Kim (Korea Univ) 26
1230 -1330 LunchSession X (Chairman H W Jung (Korea Univ) )
1330 -1345 Studies on discrete patch coating process
Yoon Dong Jung (Seoul Natl Univ) 27
1345 -1400Spontaneous Homeotropic Orientation of Nano-Cylinders Upon MorphologicalTransition from Spherical Microdomains in Block Copolymer Films
Hidekazu Yoshida (Kyoto Inst Technol) 28
1400 -1415 Particle simulation in simple shear flow
Sungup Choi (Seoul Natl Univ) 29
Session XI (Chairman T Taniguchi (Yamagata Univ) )1415 -1440 Linear and Nonlinear Rheological Behavior of Polysiloxane Gels
Hideaki Takahashi (Kyoto Univ) 30
1440 -1505 Finite element analysis of elastic solidStokes flow interaction problem
JinSuk Myung (Seoul Natl Univ) 31
1505 -1510 Closing Remarks
Poster Presentationpage
P1 Direct numerical simulation of mold filling process with (elliptic) particle filled fluidsShin Hyun Kang (Gyeongsang Natl Univ) 32
P2 Capillary spreading of drops of particulate suspensions on the solid substrateHyun Jun Jung (Gyeongsang Natl Univ) 33
P3 Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting ProcessDong Myeong Shin (Korea Univ) 34
P4 Flow Instabilities in ForwardReverse Roll Coating ProcessesSang Kwon Han (Korea Univ) 35
P5 Optimal Die InternalExternal Designs for Patch Slot CoatingSeo Hoon Shim (Korea Univ) 36
P6 Dynamics of DNA tumbling in shear to rotational mixed flowJeong Yong Lee (Korea Univ) 37
P7 Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi Kawakita (Tokyo Univ of A amp T) 38
P8 Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinningof Poly (ethylene terephthalate)
Hitoshi Hotchi (Tokyo Univ of A amp T) 39
P9 Rheology of semi-dilute solution of Ecoli DNA
Taro Kinoshita (Tokyo Univ of A amp T) 40
P10 Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki Moriya (Tokyo Univ of A amp T) 41
P11 Magnetic Orientation of Microdomains in Block Copolymer
Akifumi Yasui (Kyoto Inst Technol) 42
P12Microphase-Separated Structure and Molecular mobility of shorter end-block chain inAsymmetric Poly(methyl acrylate)-block -polystyrene-block -poly(methyl acrylate)Triblock Copolymer
Junji Fukuhara (Kyoto Inst Technol) 43
P13 High Frequency Dielectric Relaxation Behavior of Aqueous Solutions of Poly(vinylsulfate) Salts with Various Counterions
Yuichi Satokawa (Osaka Univ) 44
P14 Effects of Hydrogen-Bonds on the Dynamics of BenzylAlcohol
Shogo Nobukawa (Osaka Univ) 45
P15 High Frequency Dielectric Relaxation Behavior of Aqueous Solution ofPoly(Sulfobetaine)s
Yousuke Ono (Osaka Univ) 46
P16 Polymer conformation under fast flow
Tatsuya Iwamoto (Kyoto Univ) 47
P17 Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige (Kyoto Univ) 48
Rheological properties of novel silk fiberpoly (ε-caprolactone)
biocomposites Wei Li Xiuying Qiao Kang Sun
(State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China)
Abstract In this study novel silk fiber (SF) reinforced poly (ε-caprolactone) (PCL)
biocomposites have been fabricated and their rheological properties have been studied The novel biocomposites with appropriate mechanical properties slow degradation rate and good biocompatibility are expected to be used as internal fixation vehicles for bone However as a kind of biomaterials the composites must be sterilized before being embedded into human bodies So the electron beam irradiation treatment is used to sterilize the composites
Rheological analysis is used to study the rheological properties of the SFPCL biocomposites before and after irradiation A small amplitude dynamic oscillation test is selected and the linear viscoelastic range complex viscosity storage modulus and loss modulus are obtained The effects of fiber content and irradiation dose on the biocomposites are discussed
The silk fibers play an important role as reinforcements in improving the viscoelasitic properties of SFPCL composites Both viscosity and modulus increase as the fiber content increases and the reinforcement effect is more obviously at low frequency range than at high frequency range When adding into fiber the storage modulus reaches a plateau at low frequency indicating that when fiber content increases the interaction between fiber and fiber becomes dominant An interconnected structure between fiber and fiber is formed which requires higher shear stress and longer relaxation time for the composites to flow The increase of storage modulus is quicker than loss modulus The fiber addition changes the rheological behavior of composites from a viscous performance to an elastic-like performance However from the plots of storage modulus versus loss modulus of composites the interfacial interaction between fiber and matrix is not very strong
After being irradiated the viscosity and modulus of composites decrease as the irradiation dose increases at high frequency range and reach a maximum at a dose of 150KGy at low frequency range The plateau of storage modulus shifts to higher frequency as the irradiation dose increasing indicating that the interaction between fiber and matrix is improved by irradiation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
1
Rheological characterization of hydrogel formed by the
blend of silk fibroin and hydroxypropylcellulose
Zuguang Gong Jinrong Yao Zhengzhong Shao
The Key Laboratory of Molecular Engineering of Polymer and Department of
Macromolecular Science Fudan University Shanghai 200433 China
Silk fibroin as the dominant protein in the raw Bombyx mori silk has a bright
prospect in biomedical application for its excellent morphological plasticity and
biocompatibility Hydroxypopylcellulose as one kind of water soluble cellulose
derivatives is a biocompatible polymer used for a wide range of applications in the food
pharmaceutical and cosmetic industries In our research the hydrogels formed by silk
fibroin and hydroxypropylcellulose blends were investigated using rheology We
focused on the concentration and component ratio dependence of the gelation time and
the elastic modulus of the hydrogel while the influence of shear (shear strain and
oscillatory frequency) on the dynamics of gelation process was investigated as silk
fibroin was highly shear-sensitive in aqueous solution (in nature the silkworms
conversion of the liquid dope to the solid fibre occurs through a strain-induced phase
separation) Also it was found that the addition of ions (K+ Ca+) has an effect on the
gelation behavior of such blend
Key words silk fibroin hydroxypropylcellulose hydrogel shear rheology
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
2
Relation between electric charges and beads formation on
Electro-spinning of Poly(vinyl alcohol)
Yosuke KADOMAE Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA
Department of Polymer Science and Engineering Yamagata University 4-3-16 Jonan Yonezawa 992-8510
TEL 0238-26-3058 FAX 0238-26-3411 Email kadomaeckpssyzyamagata-uacjp
Abstract We investigate formation of beads on electro-spinning by changing conductivity of poly
vinyl alcohol (PVA) aqueous solutions and spinning conditions such as applied voltage distance (L) between the tip of needle and the collector and humidity Electric conductivity of PVA aqueous solutions was controlled by changing amount of salt (NaCl)
From the results of experiments done by changing conductivity and spinning conditions we found that the beads formation is related to electric charges at the tip of sample Formation of beads is enhanced with increasing electric conductivity of PVA aqueous solutions Additionally in cases of changing the spinning conditions beads formation is suppressed at lower electric charges When the applied voltage changes to be same electric charge in respective distances between the tip of needle and the collector beads-less fibers are fabricated in all cases as shown in Fig1
Fig1 SEM images of electro-spun fibers at the same electric charge condition (a)75kV
and L=5cm (b) 9kV and L=10cm (c) 12kV and L=15cm (d) 14kV and L=20cm
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
3
Sensitivity of Low- and High-speed Spinning Process with Flow-Induced Crystallization Kinetics
Jang Ho Yun Dong Myeong Shin Joo Sung Lee Hyun Wook Jung
and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology
Center Korea University Seoul Korea
Recent issues of the spinning process are to investigate effect of crystallization (FIC) kinetics on the spinning dynamics Doufas et al (JNNFM 2000) and Kohler et al (J Macromol Sci-Phys 2005) predicted spinline deformation by employing their two-phase crystallinity models Regarding the FIC occurring on the spinline Joo et al (JNNFM 2002) simulated the nonisothermal spinline crystallization using two-dimensional model and Lee et al (JNNFM 2005) for the first time solved the transient responses of the low-speed spinning accompanied by FIC using a one-phase crystallinity model Shin et al (Korea-Australia Rheol J 2005 Rheol Acta 2006) also adopted this model to analyze the effect of the FIC on the spinning stability and neck-like deformation in high-speed spinning by linear stability method
However sensitivity of the spinning system has not been fully elucidated yet although this is an indispensable tool for the processability and product quality in industry In this study the sensitivity of both low- and high-speed spinning processes has been scrutinized by frequency response method measuring the amplitude ratio of output with respect to the infinitesimal sinusoidal disturbances in the linearized system (Jung et al Korea J Chem Eng 2004) In the low-speed spinning case there exists an optimal crystallinity region making the system the lowest sensitive to any disturbance In the high-speed case high inertia compensates for destabilizing effect by high crystallinity and makes the system generally less sensitive leading to the reduced resonance peaks by neck-like deformation Sensitivity results have closely been correlated with the previous ones by linear stability (Shin et al 2005 2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
4
Predicting permeability for fibrous porous media based on
micro-structure with direct simulation method
Jun Feng Wang Wook Ryol Hwang Shin Hyun Kang
School of Mechanical and Aerospace Engineering Gyeongsang National University South Korea
ABSTRACT
In this study a new finite element scheme is presented to investigate the permeability of fibrous porous media which is an important parameter in the resin transfer molding simulation A representative bi-periodic domain concept is introduced such that a single cell problem with a relatively small number of fiber filaments or fiber bundles may represent a large number of repeated structures of such a cell in the transversal planar flow through fiber arrays To use the regular rectangular mesh for the entire computation we employed a finite-element fictitious-domain method similar to the distributed Lagrangian multiplier method together with the rigid-ring description of the fiber The constraint for the bi-periodic domain is implemented by the mortar element method Examples of a single domain problem with one fiber 10 fibers and randomly distributed 100 fibers are investigated the normalized permeability shows approximately a uniform function of the fiber volume fraction which makes it possible to estimate the practical average permeability of fiber tows in several micro-meter scales The predicted results agree well with existing experimental data and numerical prediction in the literature In addition we present the permeability prediction for fiber bundles and investigate the effect of orientation on the permeability
The method we developed in this study is quite well suited for predicting the permeability of fibrous porous media and investigating the flow features in different micro-scale fiber architectures along with the inter-relationship between them Since the present scheme is based on the standard velocity-pressure formulation of the finite-element method it was also easily extended to the problem with non-Newtonian fluid medium In addition the present scheme was applied to three-dimensional problems with a tri-periodic unit cell In 3D cases the predicted permeability of porous media with regular packing fiber was compared with the results of other research
KEY WORDS Microstructure Finite element analysis Permeability Direct simulation Bi-periodic frame
Acknowledgement This work has been supported by the second stage BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
5
The effect of viscosity and flow rate on the droplet size and
formation pattern in T-shaped microchannel
Duwon Choi Sung Sik Lee Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
Tel 82-2-880-1579 E-mail tetra4646parancom
Abstract
It is important to characterize the size and formation pattern in order to manipulate
the small size (piconanoliter size) of droplets for chemical and biological applications Previously Garstecki et al investigated the size and formation pattern of micron-size droplets under low viscosity ratio condition In this study we conducted the experiments of micron-size droplets generation under wide range of viscosity ratio including above 1
This experiment was performed in a confined T-shaped microchannel made by soft lithography method Immiscible two liquids glycerol aqueous solution (dispersed flow) and corn oil (carrier flow) flow in the channel with rate ranging from 003ulmin to 5ulmin in each liquid flow We changed the viscosity ratio from 002 (DI water) to 28 (glycerol 90 in water) to understand the effect of viscosity on droplet size and formation pattern
We could obtain the maps of size and formation pattern as changing flow rate and viscosity ratio We expect that these maps help predict the size of droplets and their applications such as droplet based reaction (two droplets fusion) and generation of double emulsion
[1] P Garstecki M J Furestman H A Stone and G M White 2006 Labchip 5
437-446
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
6
Transient behaviors of immiscible polymer blends under varying flow
field
QUAN CHEN WEI YU CHIXING ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering Shanghai Jiao Tong University Shanghai 200240 P R China
One frequently used method on measuring thixotropy is to perform a loop test In
which changes in the structural level like the break-up and coalescence of the drops
cause measurable thixotropic behavior (Barnes HA (1997)) The flow field in our
experiment is the round trip (RT) test in which an additional opposite trip is added on
traditional thixotropic test The breakup and coalescence mechanics under such a flow
field is discussed here In addition a new model (Yu W and Zhou C (2006)) in which
breakup and coalescence is applied in our analysis
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
7
The effect of viscosity and elasticity on the DOD (Drop-On-Demand) inkjet drop formation
A Young Lee
Byoung Wook Jo Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1879
Email twinklesnuackr
Abstract Inkjet printing is familiar as a method of printing text and images onto substrates
such as paper In the last few years it has been explored as a way of printing electrical and optical devices with the use of specialty inks For a successful inkjet printing to be achieved in this area high resolution patternability is necessary Therefore it is essential to understand the mechanism of ink drop deformation and to reduce the satellite drop which can cause defect in printing
The breakup of viscoelastic jets has been studied by many researchers with a number of dilute and semidilute poly(ethylene oxide) solutions under the gravity Similarly the presence of small amounts of polymer in Newtonian solvents can cause a significant change of the drop-on-demand drop formation This study investigates the effect of viscosity and elasticity on the drop-on-demand drop formation through the use of Newtonian liquids and low viscosity elastic liquids The satellite drop produced by breakup of main drop is easily observed by Newtonian fluids Higher viscosity can suppress this satellite drop formation to some extent and the phenomena become significant when small amount of polymer is added To quantitatively characterize the behavior of drop deformation we compared jet retraction time and breakup time by employing jet stability graphs In jet stability graph the two critical jet speeds can suggest the relative jetting stability in terms of satellite drop generation Finally the effect of imposed pulse shape on drop formation is also studied
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
8
Dielectric Studies of Polymer Chain Dynamics in Polymer Blend
JunTakada HiroshiSasaki YoshiakiMatsushima AkiraKuriyama YumiMatsumiya
TadashiInoue HiroshiWatanabe
Toagosei CoLtd and Institute for Chemical ResearchKyoto University
We examined a relationship between polymer chain dynamics and phase separated
structure in polymer blends The samples used were blends of
polyisoprene(PIPMw=199times10 3 ) and poly-tert-butylstyrene(P-t-BS-HMw=700times10 3
P-t-BS-LMw=160times10 3 ) The blend ratio was PIPP-t-BS=82(wtwt) To discuss the
changes of polymer chain dynamics we investigated the dielectric loss ε rdquo of the blend
samples and pure PIP PIP has type-A dipoles that enable us to dielectrically observe
the global motion of PIP At 30 the global motion of PIP in the blend samples was
slower than that of pure PIP This result suggests that the PIP chains are entangled
with the P-t-BS chains ie mixed in P-t-BS phase and the entanglements retards the
global motion of PIP At 70 the global motion of PIP in blend samples became close
to that of pure PIP suggesting that the PIP chains are not well entangled with P-t-BS
chains at high temperature It has been known that PIPP-t-BS blends exhibit
LCST-type phase behavior Changes of the global motion of PIP in blend samples with
temperature is consistent with this phase behavior
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
9
Normal stress development under large amplitude oscillatory
shear flow
Jung Gun Nam Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email guns2snuackr
Abstract The dynamic response of viscoelastic fluids under large amplitude oscillatory shear (LAOS) has been a subject of long history In recent years there seem to be progresses in this field More advanced instrumentation and new concepts are emerging In the LAOS flow the analysis has been mostly focused on shear stress possibly due to the lack of accurate measurement of normal stress However the normal stress may become larger than shear stress at high strain amplitudes and there are good reasons we need to understand the normal stress behavior As the instrumentation advances it becomes more feasible to get reliable data and this field will be more challenging The purpose of this paper is to develop a research platform to analyze and thereby to understand the normal stress behavior of complex fluids under LAOS flow We take the Giesekus model as a representative constitutive model and investigate diverse responses of the model We define new dynamic properties corresponding to normal stresses in a similar way to define dynamic moduli from shear stress and examine their behavior with various analyzing tools Experimental data are also compared with model predictions Though it is not yet possible to compare all the predictions due to instrumental limitation the prediction fits well with the experimental data and we hope this study provide a useful framework for further understanding of the nonlinear behavior of complex fluids under LAOS flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
10
Nonlinear behavior of complex fluids under large amplitude
oscillatory shear and squeezing flow
Juha Hwang
Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1580
Email jindols79hotmailcom
Abstract
The purpose of this research is to figure out viscoelastic behavior under large amplitude oscillatory shear (LAOS) and squeezing flow To analyze this behavior we have applied following nonlinear constitutive equations Upper convected Maxwell Giesekus FENE-P Marrucci Leonov Larson and Pom-pom model We analyzed the simulation results by modulus Fourier transform and stress decomposition which distinguishes elastic from viscous contribution to total stress The simulation results were compared with experimental data in other literatures Most constitutive equations predict LAOS behavior qualitatively in shear flow while only Larson model predicts LAOS behavior in squeezing flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
11
Studies on micro-convections induced in a polymer solution heated from above Yasuhiro YAMADA Shinichi SAKURAI
Polymer Science amp Engineering Kyoto Institute of Technology Kyoto Japan
We have reported micro-convections induced by the Soret effect in a polystyrene (PS)dioctylphthalate (DOP) solution under a temperature gradient (heated from below) The Soret effect stands for the fact that the concentration gradient is induced under the applied temperature gradient When temperature gradient is formed in a PSDOP solution PS is accumulated in the cooler side (upper side) by the Soret effect Then the concentrated PS solution undergoes sedimentation because the density of PS is higher than DOP Since this event can take place and result in a convective motion in a considerably thin layer of the solution (say 01 mm thickness) we refer to this as ldquomicro-convectionrdquo If the solvent density is larger than polymer a micro-convection can be induced even when such a solution is heated from above To examine this speculation we conducted experiments on a PStricresylphosphate (TCP) solution heated from above Note that the density of the solvent (TCP) is higher than that of PS Densities are 098 117 and 105 (gcm2) for DOP TCP and PS respectively
The samples used were PS (Mw=200k and MwMn=105) as a solute and TCP as a solvent The weight compositions are in the range of 01999 ~ 50950 The polymer solution was confined in a 05mm thickness layer Temperatures at the top and bottom plates Ttop and Tbot respectively were controlled independently by circulating temperature-regulated water being Ttop and Tbot at 35 and 65 respectively We observed such the polymer solution under a phase-contrast microscope As a result it was found that convection was generated in PSTCP solutions even when heated from above instead of being heated from below Fig 1 shows a typical result of a phase-contrast microscopic observation for the PSTCP sample (50950 composition) heated from below (a) and from above (b) In addition we analyzed dark meshes of convection to obtain brightness of the dark meshes based on which temporal changes in convection activity were examined In Fig2 were shown temporal changes in the brightness of the dark mesh for the PSTCP sample (50950 composition) Some oscillations were found and the brightness finally reached an asymptotic value It is interesting to note that a similar behavior was seen for the case of a PSDOP solution heated from bottom although the direction of the energy input is opposed
---------------------------------------------------------------------------------------------------------------- Corresponding author e-mail d2jyasmailgoonejp TEL 075-724-7864 FAX 075-724-7800
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
12
Development of a mixed-flow rheometer
Jae Hee Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email exodus55snuackr
Abstract This paper is concerned with the development of a mixed-flow rheometer for
determining the viscosity of a highly viscous filled viscoplastic fluid Recently there has been a renewal of interest in mixed-flow of viscoelastic fluid It is difficult to characterize the viscoelastic materials using conventional rheometer such as capillary rotational and compressional rheometers
In this study we develop a new rheometer for analysis of mixed-flow which is the combination of shear and compression mode This rheometer is designed for investigating the different microstructural rearrangement processes by the combination of two-deformation modes It is important to understand the combined-mode within an industrial quality control environment
In this presentation we will summarize the recent method for determination of the properties of viscoelastic systems under mixed-flow and provide a comprehensive mathematical theory for the interpretation of experimental data from the mixed-flow rheometer considering the influence of fluid inertia Also a series of experiments were carried out on a number of viscoelastic systems to confirm the theory
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
13
Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA Tadamine KIMU Hideshige SUZUKI Akihiro NISHIOKA
Tomonori KODA and Susumu IKEDA Department of Polymer Science and Engineering Yamagata University
Ikeda laboratry Yonezawa 992-8510 Japan E-mail dmx13313dipyzyamagata-uacjp
The purpose of this study is to clarify Ferroelectricity and Crystallization in
Poly(vinylidene fluoride)clay nanocomposites The ferroelectoricity in PVDFclay nanocomposites have been examined by measuring the D-E hysteresis loops The composites were also characterized by XRD DSC and TEM The nanocomposites were prepared by using melt compounding method This compounding was carried out by using the Twin Screw Extruder (TECHNOVEL Co Ltd model KZW-30 LD = 45) All samples for measurement were produced by hot press method at 200oC from dried pellet samples
As a result we found that the ferroelectricity can be observed in non-stretched PVDFclay nanocomposites films The PVDF crystal structure in its nanocomposites was similar to β form This results means that blending small amount of nano is one of the way to induce ferroelecticity of PVDF without stretching To clarify the mechanism of the induction ferroelecticity we have estimated lattice spacing of a clay surface by XRD The spacing between negatively charged oxygens on a clay surface is about 257Å which is almost the same spacing of monomer unit of PVDF in all trans chain conformation PVDF monomer on negatively charged clay surface has a permanent electrical dipole moment PVDF crystallites are epitaxially grown up on the clay surface in accordance with surface lattice structure
Acknowledgement We would like to thank for the cooperation of Prof KHAhn and all members of his
Laboratory in Seoul National University (SNU) Korea We would like to thank for providing us with TEM photos of our samples I would also like to thank Mr Namkung Mr Kim and Prof KH Ahn for their valuable comments suggestions support during my stay in Seoul National University (SNU)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
14
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
2007127Session IV (Chairman YD Kwon (Sungkyunkwan Univ) )
page
930 -955 Normal stress development under large amplitude oscillatory shear flow
Jung Gun Nam (Seoul Natl Univ) 10
955 -1010Nonlinear behavior of complex fluids under large amplitude oscillatory shear andsqueezing flow
Juha Hwang (Seoul Natl Univ) 11
1010 -1025 Studies on micro-convections induced in a polymer solution heated from above
Yasuhiro YAMADA (Kyoto Inst Technol) 12
Session V (Chairman K Sun (Shanghai Jiao Tong Univ) )1025 -1040 Development of a mixed-flow rheometer
Jae Hee Kim (Seoul Natl Univ) 13
1040 -1105 Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA (Yamagata Univ) 14
1105 -1130 Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim (Seoul Natl Univ) 15
1130 -1150 Coffee BreakSession VI (Chairman K H Ahn (Seoul Natl Univ) )
1150 -1215 The Effect of Shear Flow on the Reaction of POE with Peroxide
Jianye Liu (Shanghai Jiao Tong Univ) 16
1215 -1230Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient ShearFlow ----
Hideyuki UEMATSU (Yamagata Univ) 17
1230 -1245Investigation of polyethylene coupling reaction initiated by Dicumyl peroxideoccurred in Haake internal mixer using two-dimensional numerical simulation method
Ji Zhou (Shanghai Jiao Tong Univ) 18
1245 -1340 Lunch1340 -1800 Free Discussion1800 -2000 Dinner
2007128Session VII (Chairman W Yu (Shanghai Jiao Tong Univ) )
930 -945 Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki Sato (Tokyo Univ of A amp T) 19
945 -1010A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles and their surfacecoating
Ke Tao (Shanghai Jiao Tong Univ) 20
1010 -1025 Particle Tracking in a drying process
So Youn Kim (Seoul Natl Univ) 21
Session VIII (Chairman Y Masubuchi (Tokyo Univ of A amp T) )page
1025 -1050Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong (Kyoto Inst Technol) 22
1050 -1115 Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin (Korea Univ) 23
1115 -1130Measuring viscoelastic behavior of dilute suspensions with particle trackingmicrorheology
Heekyoung Kang (Seoul Natl Univ) 24
1130 -1150 Coffee BreakSession IX (Chairman S Sakurai (Kyoto Inst Technol) )
1150 -1215 Stress development in suspension coating process
Sunhyung Kim (Seoul Natl Univ) 25
1215 -1230Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in SteelProducts
Hak-Yul Kim (Korea Univ) 26
1230 -1330 LunchSession X (Chairman H W Jung (Korea Univ) )
1330 -1345 Studies on discrete patch coating process
Yoon Dong Jung (Seoul Natl Univ) 27
1345 -1400Spontaneous Homeotropic Orientation of Nano-Cylinders Upon MorphologicalTransition from Spherical Microdomains in Block Copolymer Films
Hidekazu Yoshida (Kyoto Inst Technol) 28
1400 -1415 Particle simulation in simple shear flow
Sungup Choi (Seoul Natl Univ) 29
Session XI (Chairman T Taniguchi (Yamagata Univ) )1415 -1440 Linear and Nonlinear Rheological Behavior of Polysiloxane Gels
Hideaki Takahashi (Kyoto Univ) 30
1440 -1505 Finite element analysis of elastic solidStokes flow interaction problem
JinSuk Myung (Seoul Natl Univ) 31
1505 -1510 Closing Remarks
Poster Presentationpage
P1 Direct numerical simulation of mold filling process with (elliptic) particle filled fluidsShin Hyun Kang (Gyeongsang Natl Univ) 32
P2 Capillary spreading of drops of particulate suspensions on the solid substrateHyun Jun Jung (Gyeongsang Natl Univ) 33
P3 Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting ProcessDong Myeong Shin (Korea Univ) 34
P4 Flow Instabilities in ForwardReverse Roll Coating ProcessesSang Kwon Han (Korea Univ) 35
P5 Optimal Die InternalExternal Designs for Patch Slot CoatingSeo Hoon Shim (Korea Univ) 36
P6 Dynamics of DNA tumbling in shear to rotational mixed flowJeong Yong Lee (Korea Univ) 37
P7 Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi Kawakita (Tokyo Univ of A amp T) 38
P8 Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinningof Poly (ethylene terephthalate)
Hitoshi Hotchi (Tokyo Univ of A amp T) 39
P9 Rheology of semi-dilute solution of Ecoli DNA
Taro Kinoshita (Tokyo Univ of A amp T) 40
P10 Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki Moriya (Tokyo Univ of A amp T) 41
P11 Magnetic Orientation of Microdomains in Block Copolymer
Akifumi Yasui (Kyoto Inst Technol) 42
P12Microphase-Separated Structure and Molecular mobility of shorter end-block chain inAsymmetric Poly(methyl acrylate)-block -polystyrene-block -poly(methyl acrylate)Triblock Copolymer
Junji Fukuhara (Kyoto Inst Technol) 43
P13 High Frequency Dielectric Relaxation Behavior of Aqueous Solutions of Poly(vinylsulfate) Salts with Various Counterions
Yuichi Satokawa (Osaka Univ) 44
P14 Effects of Hydrogen-Bonds on the Dynamics of BenzylAlcohol
Shogo Nobukawa (Osaka Univ) 45
P15 High Frequency Dielectric Relaxation Behavior of Aqueous Solution ofPoly(Sulfobetaine)s
Yousuke Ono (Osaka Univ) 46
P16 Polymer conformation under fast flow
Tatsuya Iwamoto (Kyoto Univ) 47
P17 Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige (Kyoto Univ) 48
Rheological properties of novel silk fiberpoly (ε-caprolactone)
biocomposites Wei Li Xiuying Qiao Kang Sun
(State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China)
Abstract In this study novel silk fiber (SF) reinforced poly (ε-caprolactone) (PCL)
biocomposites have been fabricated and their rheological properties have been studied The novel biocomposites with appropriate mechanical properties slow degradation rate and good biocompatibility are expected to be used as internal fixation vehicles for bone However as a kind of biomaterials the composites must be sterilized before being embedded into human bodies So the electron beam irradiation treatment is used to sterilize the composites
Rheological analysis is used to study the rheological properties of the SFPCL biocomposites before and after irradiation A small amplitude dynamic oscillation test is selected and the linear viscoelastic range complex viscosity storage modulus and loss modulus are obtained The effects of fiber content and irradiation dose on the biocomposites are discussed
The silk fibers play an important role as reinforcements in improving the viscoelasitic properties of SFPCL composites Both viscosity and modulus increase as the fiber content increases and the reinforcement effect is more obviously at low frequency range than at high frequency range When adding into fiber the storage modulus reaches a plateau at low frequency indicating that when fiber content increases the interaction between fiber and fiber becomes dominant An interconnected structure between fiber and fiber is formed which requires higher shear stress and longer relaxation time for the composites to flow The increase of storage modulus is quicker than loss modulus The fiber addition changes the rheological behavior of composites from a viscous performance to an elastic-like performance However from the plots of storage modulus versus loss modulus of composites the interfacial interaction between fiber and matrix is not very strong
After being irradiated the viscosity and modulus of composites decrease as the irradiation dose increases at high frequency range and reach a maximum at a dose of 150KGy at low frequency range The plateau of storage modulus shifts to higher frequency as the irradiation dose increasing indicating that the interaction between fiber and matrix is improved by irradiation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
1
Rheological characterization of hydrogel formed by the
blend of silk fibroin and hydroxypropylcellulose
Zuguang Gong Jinrong Yao Zhengzhong Shao
The Key Laboratory of Molecular Engineering of Polymer and Department of
Macromolecular Science Fudan University Shanghai 200433 China
Silk fibroin as the dominant protein in the raw Bombyx mori silk has a bright
prospect in biomedical application for its excellent morphological plasticity and
biocompatibility Hydroxypopylcellulose as one kind of water soluble cellulose
derivatives is a biocompatible polymer used for a wide range of applications in the food
pharmaceutical and cosmetic industries In our research the hydrogels formed by silk
fibroin and hydroxypropylcellulose blends were investigated using rheology We
focused on the concentration and component ratio dependence of the gelation time and
the elastic modulus of the hydrogel while the influence of shear (shear strain and
oscillatory frequency) on the dynamics of gelation process was investigated as silk
fibroin was highly shear-sensitive in aqueous solution (in nature the silkworms
conversion of the liquid dope to the solid fibre occurs through a strain-induced phase
separation) Also it was found that the addition of ions (K+ Ca+) has an effect on the
gelation behavior of such blend
Key words silk fibroin hydroxypropylcellulose hydrogel shear rheology
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
2
Relation between electric charges and beads formation on
Electro-spinning of Poly(vinyl alcohol)
Yosuke KADOMAE Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA
Department of Polymer Science and Engineering Yamagata University 4-3-16 Jonan Yonezawa 992-8510
TEL 0238-26-3058 FAX 0238-26-3411 Email kadomaeckpssyzyamagata-uacjp
Abstract We investigate formation of beads on electro-spinning by changing conductivity of poly
vinyl alcohol (PVA) aqueous solutions and spinning conditions such as applied voltage distance (L) between the tip of needle and the collector and humidity Electric conductivity of PVA aqueous solutions was controlled by changing amount of salt (NaCl)
From the results of experiments done by changing conductivity and spinning conditions we found that the beads formation is related to electric charges at the tip of sample Formation of beads is enhanced with increasing electric conductivity of PVA aqueous solutions Additionally in cases of changing the spinning conditions beads formation is suppressed at lower electric charges When the applied voltage changes to be same electric charge in respective distances between the tip of needle and the collector beads-less fibers are fabricated in all cases as shown in Fig1
Fig1 SEM images of electro-spun fibers at the same electric charge condition (a)75kV
and L=5cm (b) 9kV and L=10cm (c) 12kV and L=15cm (d) 14kV and L=20cm
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
3
Sensitivity of Low- and High-speed Spinning Process with Flow-Induced Crystallization Kinetics
Jang Ho Yun Dong Myeong Shin Joo Sung Lee Hyun Wook Jung
and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology
Center Korea University Seoul Korea
Recent issues of the spinning process are to investigate effect of crystallization (FIC) kinetics on the spinning dynamics Doufas et al (JNNFM 2000) and Kohler et al (J Macromol Sci-Phys 2005) predicted spinline deformation by employing their two-phase crystallinity models Regarding the FIC occurring on the spinline Joo et al (JNNFM 2002) simulated the nonisothermal spinline crystallization using two-dimensional model and Lee et al (JNNFM 2005) for the first time solved the transient responses of the low-speed spinning accompanied by FIC using a one-phase crystallinity model Shin et al (Korea-Australia Rheol J 2005 Rheol Acta 2006) also adopted this model to analyze the effect of the FIC on the spinning stability and neck-like deformation in high-speed spinning by linear stability method
However sensitivity of the spinning system has not been fully elucidated yet although this is an indispensable tool for the processability and product quality in industry In this study the sensitivity of both low- and high-speed spinning processes has been scrutinized by frequency response method measuring the amplitude ratio of output with respect to the infinitesimal sinusoidal disturbances in the linearized system (Jung et al Korea J Chem Eng 2004) In the low-speed spinning case there exists an optimal crystallinity region making the system the lowest sensitive to any disturbance In the high-speed case high inertia compensates for destabilizing effect by high crystallinity and makes the system generally less sensitive leading to the reduced resonance peaks by neck-like deformation Sensitivity results have closely been correlated with the previous ones by linear stability (Shin et al 2005 2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
4
Predicting permeability for fibrous porous media based on
micro-structure with direct simulation method
Jun Feng Wang Wook Ryol Hwang Shin Hyun Kang
School of Mechanical and Aerospace Engineering Gyeongsang National University South Korea
ABSTRACT
In this study a new finite element scheme is presented to investigate the permeability of fibrous porous media which is an important parameter in the resin transfer molding simulation A representative bi-periodic domain concept is introduced such that a single cell problem with a relatively small number of fiber filaments or fiber bundles may represent a large number of repeated structures of such a cell in the transversal planar flow through fiber arrays To use the regular rectangular mesh for the entire computation we employed a finite-element fictitious-domain method similar to the distributed Lagrangian multiplier method together with the rigid-ring description of the fiber The constraint for the bi-periodic domain is implemented by the mortar element method Examples of a single domain problem with one fiber 10 fibers and randomly distributed 100 fibers are investigated the normalized permeability shows approximately a uniform function of the fiber volume fraction which makes it possible to estimate the practical average permeability of fiber tows in several micro-meter scales The predicted results agree well with existing experimental data and numerical prediction in the literature In addition we present the permeability prediction for fiber bundles and investigate the effect of orientation on the permeability
The method we developed in this study is quite well suited for predicting the permeability of fibrous porous media and investigating the flow features in different micro-scale fiber architectures along with the inter-relationship between them Since the present scheme is based on the standard velocity-pressure formulation of the finite-element method it was also easily extended to the problem with non-Newtonian fluid medium In addition the present scheme was applied to three-dimensional problems with a tri-periodic unit cell In 3D cases the predicted permeability of porous media with regular packing fiber was compared with the results of other research
KEY WORDS Microstructure Finite element analysis Permeability Direct simulation Bi-periodic frame
Acknowledgement This work has been supported by the second stage BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
5
The effect of viscosity and flow rate on the droplet size and
formation pattern in T-shaped microchannel
Duwon Choi Sung Sik Lee Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
Tel 82-2-880-1579 E-mail tetra4646parancom
Abstract
It is important to characterize the size and formation pattern in order to manipulate
the small size (piconanoliter size) of droplets for chemical and biological applications Previously Garstecki et al investigated the size and formation pattern of micron-size droplets under low viscosity ratio condition In this study we conducted the experiments of micron-size droplets generation under wide range of viscosity ratio including above 1
This experiment was performed in a confined T-shaped microchannel made by soft lithography method Immiscible two liquids glycerol aqueous solution (dispersed flow) and corn oil (carrier flow) flow in the channel with rate ranging from 003ulmin to 5ulmin in each liquid flow We changed the viscosity ratio from 002 (DI water) to 28 (glycerol 90 in water) to understand the effect of viscosity on droplet size and formation pattern
We could obtain the maps of size and formation pattern as changing flow rate and viscosity ratio We expect that these maps help predict the size of droplets and their applications such as droplet based reaction (two droplets fusion) and generation of double emulsion
[1] P Garstecki M J Furestman H A Stone and G M White 2006 Labchip 5
437-446
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
6
Transient behaviors of immiscible polymer blends under varying flow
field
QUAN CHEN WEI YU CHIXING ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering Shanghai Jiao Tong University Shanghai 200240 P R China
One frequently used method on measuring thixotropy is to perform a loop test In
which changes in the structural level like the break-up and coalescence of the drops
cause measurable thixotropic behavior (Barnes HA (1997)) The flow field in our
experiment is the round trip (RT) test in which an additional opposite trip is added on
traditional thixotropic test The breakup and coalescence mechanics under such a flow
field is discussed here In addition a new model (Yu W and Zhou C (2006)) in which
breakup and coalescence is applied in our analysis
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
7
The effect of viscosity and elasticity on the DOD (Drop-On-Demand) inkjet drop formation
A Young Lee
Byoung Wook Jo Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1879
Email twinklesnuackr
Abstract Inkjet printing is familiar as a method of printing text and images onto substrates
such as paper In the last few years it has been explored as a way of printing electrical and optical devices with the use of specialty inks For a successful inkjet printing to be achieved in this area high resolution patternability is necessary Therefore it is essential to understand the mechanism of ink drop deformation and to reduce the satellite drop which can cause defect in printing
The breakup of viscoelastic jets has been studied by many researchers with a number of dilute and semidilute poly(ethylene oxide) solutions under the gravity Similarly the presence of small amounts of polymer in Newtonian solvents can cause a significant change of the drop-on-demand drop formation This study investigates the effect of viscosity and elasticity on the drop-on-demand drop formation through the use of Newtonian liquids and low viscosity elastic liquids The satellite drop produced by breakup of main drop is easily observed by Newtonian fluids Higher viscosity can suppress this satellite drop formation to some extent and the phenomena become significant when small amount of polymer is added To quantitatively characterize the behavior of drop deformation we compared jet retraction time and breakup time by employing jet stability graphs In jet stability graph the two critical jet speeds can suggest the relative jetting stability in terms of satellite drop generation Finally the effect of imposed pulse shape on drop formation is also studied
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
8
Dielectric Studies of Polymer Chain Dynamics in Polymer Blend
JunTakada HiroshiSasaki YoshiakiMatsushima AkiraKuriyama YumiMatsumiya
TadashiInoue HiroshiWatanabe
Toagosei CoLtd and Institute for Chemical ResearchKyoto University
We examined a relationship between polymer chain dynamics and phase separated
structure in polymer blends The samples used were blends of
polyisoprene(PIPMw=199times10 3 ) and poly-tert-butylstyrene(P-t-BS-HMw=700times10 3
P-t-BS-LMw=160times10 3 ) The blend ratio was PIPP-t-BS=82(wtwt) To discuss the
changes of polymer chain dynamics we investigated the dielectric loss ε rdquo of the blend
samples and pure PIP PIP has type-A dipoles that enable us to dielectrically observe
the global motion of PIP At 30 the global motion of PIP in the blend samples was
slower than that of pure PIP This result suggests that the PIP chains are entangled
with the P-t-BS chains ie mixed in P-t-BS phase and the entanglements retards the
global motion of PIP At 70 the global motion of PIP in blend samples became close
to that of pure PIP suggesting that the PIP chains are not well entangled with P-t-BS
chains at high temperature It has been known that PIPP-t-BS blends exhibit
LCST-type phase behavior Changes of the global motion of PIP in blend samples with
temperature is consistent with this phase behavior
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
9
Normal stress development under large amplitude oscillatory
shear flow
Jung Gun Nam Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email guns2snuackr
Abstract The dynamic response of viscoelastic fluids under large amplitude oscillatory shear (LAOS) has been a subject of long history In recent years there seem to be progresses in this field More advanced instrumentation and new concepts are emerging In the LAOS flow the analysis has been mostly focused on shear stress possibly due to the lack of accurate measurement of normal stress However the normal stress may become larger than shear stress at high strain amplitudes and there are good reasons we need to understand the normal stress behavior As the instrumentation advances it becomes more feasible to get reliable data and this field will be more challenging The purpose of this paper is to develop a research platform to analyze and thereby to understand the normal stress behavior of complex fluids under LAOS flow We take the Giesekus model as a representative constitutive model and investigate diverse responses of the model We define new dynamic properties corresponding to normal stresses in a similar way to define dynamic moduli from shear stress and examine their behavior with various analyzing tools Experimental data are also compared with model predictions Though it is not yet possible to compare all the predictions due to instrumental limitation the prediction fits well with the experimental data and we hope this study provide a useful framework for further understanding of the nonlinear behavior of complex fluids under LAOS flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
10
Nonlinear behavior of complex fluids under large amplitude
oscillatory shear and squeezing flow
Juha Hwang
Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1580
Email jindols79hotmailcom
Abstract
The purpose of this research is to figure out viscoelastic behavior under large amplitude oscillatory shear (LAOS) and squeezing flow To analyze this behavior we have applied following nonlinear constitutive equations Upper convected Maxwell Giesekus FENE-P Marrucci Leonov Larson and Pom-pom model We analyzed the simulation results by modulus Fourier transform and stress decomposition which distinguishes elastic from viscous contribution to total stress The simulation results were compared with experimental data in other literatures Most constitutive equations predict LAOS behavior qualitatively in shear flow while only Larson model predicts LAOS behavior in squeezing flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
11
Studies on micro-convections induced in a polymer solution heated from above Yasuhiro YAMADA Shinichi SAKURAI
Polymer Science amp Engineering Kyoto Institute of Technology Kyoto Japan
We have reported micro-convections induced by the Soret effect in a polystyrene (PS)dioctylphthalate (DOP) solution under a temperature gradient (heated from below) The Soret effect stands for the fact that the concentration gradient is induced under the applied temperature gradient When temperature gradient is formed in a PSDOP solution PS is accumulated in the cooler side (upper side) by the Soret effect Then the concentrated PS solution undergoes sedimentation because the density of PS is higher than DOP Since this event can take place and result in a convective motion in a considerably thin layer of the solution (say 01 mm thickness) we refer to this as ldquomicro-convectionrdquo If the solvent density is larger than polymer a micro-convection can be induced even when such a solution is heated from above To examine this speculation we conducted experiments on a PStricresylphosphate (TCP) solution heated from above Note that the density of the solvent (TCP) is higher than that of PS Densities are 098 117 and 105 (gcm2) for DOP TCP and PS respectively
The samples used were PS (Mw=200k and MwMn=105) as a solute and TCP as a solvent The weight compositions are in the range of 01999 ~ 50950 The polymer solution was confined in a 05mm thickness layer Temperatures at the top and bottom plates Ttop and Tbot respectively were controlled independently by circulating temperature-regulated water being Ttop and Tbot at 35 and 65 respectively We observed such the polymer solution under a phase-contrast microscope As a result it was found that convection was generated in PSTCP solutions even when heated from above instead of being heated from below Fig 1 shows a typical result of a phase-contrast microscopic observation for the PSTCP sample (50950 composition) heated from below (a) and from above (b) In addition we analyzed dark meshes of convection to obtain brightness of the dark meshes based on which temporal changes in convection activity were examined In Fig2 were shown temporal changes in the brightness of the dark mesh for the PSTCP sample (50950 composition) Some oscillations were found and the brightness finally reached an asymptotic value It is interesting to note that a similar behavior was seen for the case of a PSDOP solution heated from bottom although the direction of the energy input is opposed
---------------------------------------------------------------------------------------------------------------- Corresponding author e-mail d2jyasmailgoonejp TEL 075-724-7864 FAX 075-724-7800
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
12
Development of a mixed-flow rheometer
Jae Hee Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email exodus55snuackr
Abstract This paper is concerned with the development of a mixed-flow rheometer for
determining the viscosity of a highly viscous filled viscoplastic fluid Recently there has been a renewal of interest in mixed-flow of viscoelastic fluid It is difficult to characterize the viscoelastic materials using conventional rheometer such as capillary rotational and compressional rheometers
In this study we develop a new rheometer for analysis of mixed-flow which is the combination of shear and compression mode This rheometer is designed for investigating the different microstructural rearrangement processes by the combination of two-deformation modes It is important to understand the combined-mode within an industrial quality control environment
In this presentation we will summarize the recent method for determination of the properties of viscoelastic systems under mixed-flow and provide a comprehensive mathematical theory for the interpretation of experimental data from the mixed-flow rheometer considering the influence of fluid inertia Also a series of experiments were carried out on a number of viscoelastic systems to confirm the theory
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
13
Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA Tadamine KIMU Hideshige SUZUKI Akihiro NISHIOKA
Tomonori KODA and Susumu IKEDA Department of Polymer Science and Engineering Yamagata University
Ikeda laboratry Yonezawa 992-8510 Japan E-mail dmx13313dipyzyamagata-uacjp
The purpose of this study is to clarify Ferroelectricity and Crystallization in
Poly(vinylidene fluoride)clay nanocomposites The ferroelectoricity in PVDFclay nanocomposites have been examined by measuring the D-E hysteresis loops The composites were also characterized by XRD DSC and TEM The nanocomposites were prepared by using melt compounding method This compounding was carried out by using the Twin Screw Extruder (TECHNOVEL Co Ltd model KZW-30 LD = 45) All samples for measurement were produced by hot press method at 200oC from dried pellet samples
As a result we found that the ferroelectricity can be observed in non-stretched PVDFclay nanocomposites films The PVDF crystal structure in its nanocomposites was similar to β form This results means that blending small amount of nano is one of the way to induce ferroelecticity of PVDF without stretching To clarify the mechanism of the induction ferroelecticity we have estimated lattice spacing of a clay surface by XRD The spacing between negatively charged oxygens on a clay surface is about 257Å which is almost the same spacing of monomer unit of PVDF in all trans chain conformation PVDF monomer on negatively charged clay surface has a permanent electrical dipole moment PVDF crystallites are epitaxially grown up on the clay surface in accordance with surface lattice structure
Acknowledgement We would like to thank for the cooperation of Prof KHAhn and all members of his
Laboratory in Seoul National University (SNU) Korea We would like to thank for providing us with TEM photos of our samples I would also like to thank Mr Namkung Mr Kim and Prof KH Ahn for their valuable comments suggestions support during my stay in Seoul National University (SNU)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
14
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Session VIII (Chairman Y Masubuchi (Tokyo Univ of A amp T) )page
1025 -1050Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong (Kyoto Inst Technol) 22
1050 -1115 Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin (Korea Univ) 23
1115 -1130Measuring viscoelastic behavior of dilute suspensions with particle trackingmicrorheology
Heekyoung Kang (Seoul Natl Univ) 24
1130 -1150 Coffee BreakSession IX (Chairman S Sakurai (Kyoto Inst Technol) )
1150 -1215 Stress development in suspension coating process
Sunhyung Kim (Seoul Natl Univ) 25
1215 -1230Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in SteelProducts
Hak-Yul Kim (Korea Univ) 26
1230 -1330 LunchSession X (Chairman H W Jung (Korea Univ) )
1330 -1345 Studies on discrete patch coating process
Yoon Dong Jung (Seoul Natl Univ) 27
1345 -1400Spontaneous Homeotropic Orientation of Nano-Cylinders Upon MorphologicalTransition from Spherical Microdomains in Block Copolymer Films
Hidekazu Yoshida (Kyoto Inst Technol) 28
1400 -1415 Particle simulation in simple shear flow
Sungup Choi (Seoul Natl Univ) 29
Session XI (Chairman T Taniguchi (Yamagata Univ) )1415 -1440 Linear and Nonlinear Rheological Behavior of Polysiloxane Gels
Hideaki Takahashi (Kyoto Univ) 30
1440 -1505 Finite element analysis of elastic solidStokes flow interaction problem
JinSuk Myung (Seoul Natl Univ) 31
1505 -1510 Closing Remarks
Poster Presentationpage
P1 Direct numerical simulation of mold filling process with (elliptic) particle filled fluidsShin Hyun Kang (Gyeongsang Natl Univ) 32
P2 Capillary spreading of drops of particulate suspensions on the solid substrateHyun Jun Jung (Gyeongsang Natl Univ) 33
P3 Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting ProcessDong Myeong Shin (Korea Univ) 34
P4 Flow Instabilities in ForwardReverse Roll Coating ProcessesSang Kwon Han (Korea Univ) 35
P5 Optimal Die InternalExternal Designs for Patch Slot CoatingSeo Hoon Shim (Korea Univ) 36
P6 Dynamics of DNA tumbling in shear to rotational mixed flowJeong Yong Lee (Korea Univ) 37
P7 Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi Kawakita (Tokyo Univ of A amp T) 38
P8 Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinningof Poly (ethylene terephthalate)
Hitoshi Hotchi (Tokyo Univ of A amp T) 39
P9 Rheology of semi-dilute solution of Ecoli DNA
Taro Kinoshita (Tokyo Univ of A amp T) 40
P10 Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki Moriya (Tokyo Univ of A amp T) 41
P11 Magnetic Orientation of Microdomains in Block Copolymer
Akifumi Yasui (Kyoto Inst Technol) 42
P12Microphase-Separated Structure and Molecular mobility of shorter end-block chain inAsymmetric Poly(methyl acrylate)-block -polystyrene-block -poly(methyl acrylate)Triblock Copolymer
Junji Fukuhara (Kyoto Inst Technol) 43
P13 High Frequency Dielectric Relaxation Behavior of Aqueous Solutions of Poly(vinylsulfate) Salts with Various Counterions
Yuichi Satokawa (Osaka Univ) 44
P14 Effects of Hydrogen-Bonds on the Dynamics of BenzylAlcohol
Shogo Nobukawa (Osaka Univ) 45
P15 High Frequency Dielectric Relaxation Behavior of Aqueous Solution ofPoly(Sulfobetaine)s
Yousuke Ono (Osaka Univ) 46
P16 Polymer conformation under fast flow
Tatsuya Iwamoto (Kyoto Univ) 47
P17 Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige (Kyoto Univ) 48
Rheological properties of novel silk fiberpoly (ε-caprolactone)
biocomposites Wei Li Xiuying Qiao Kang Sun
(State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China)
Abstract In this study novel silk fiber (SF) reinforced poly (ε-caprolactone) (PCL)
biocomposites have been fabricated and their rheological properties have been studied The novel biocomposites with appropriate mechanical properties slow degradation rate and good biocompatibility are expected to be used as internal fixation vehicles for bone However as a kind of biomaterials the composites must be sterilized before being embedded into human bodies So the electron beam irradiation treatment is used to sterilize the composites
Rheological analysis is used to study the rheological properties of the SFPCL biocomposites before and after irradiation A small amplitude dynamic oscillation test is selected and the linear viscoelastic range complex viscosity storage modulus and loss modulus are obtained The effects of fiber content and irradiation dose on the biocomposites are discussed
The silk fibers play an important role as reinforcements in improving the viscoelasitic properties of SFPCL composites Both viscosity and modulus increase as the fiber content increases and the reinforcement effect is more obviously at low frequency range than at high frequency range When adding into fiber the storage modulus reaches a plateau at low frequency indicating that when fiber content increases the interaction between fiber and fiber becomes dominant An interconnected structure between fiber and fiber is formed which requires higher shear stress and longer relaxation time for the composites to flow The increase of storage modulus is quicker than loss modulus The fiber addition changes the rheological behavior of composites from a viscous performance to an elastic-like performance However from the plots of storage modulus versus loss modulus of composites the interfacial interaction between fiber and matrix is not very strong
After being irradiated the viscosity and modulus of composites decrease as the irradiation dose increases at high frequency range and reach a maximum at a dose of 150KGy at low frequency range The plateau of storage modulus shifts to higher frequency as the irradiation dose increasing indicating that the interaction between fiber and matrix is improved by irradiation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
1
Rheological characterization of hydrogel formed by the
blend of silk fibroin and hydroxypropylcellulose
Zuguang Gong Jinrong Yao Zhengzhong Shao
The Key Laboratory of Molecular Engineering of Polymer and Department of
Macromolecular Science Fudan University Shanghai 200433 China
Silk fibroin as the dominant protein in the raw Bombyx mori silk has a bright
prospect in biomedical application for its excellent morphological plasticity and
biocompatibility Hydroxypopylcellulose as one kind of water soluble cellulose
derivatives is a biocompatible polymer used for a wide range of applications in the food
pharmaceutical and cosmetic industries In our research the hydrogels formed by silk
fibroin and hydroxypropylcellulose blends were investigated using rheology We
focused on the concentration and component ratio dependence of the gelation time and
the elastic modulus of the hydrogel while the influence of shear (shear strain and
oscillatory frequency) on the dynamics of gelation process was investigated as silk
fibroin was highly shear-sensitive in aqueous solution (in nature the silkworms
conversion of the liquid dope to the solid fibre occurs through a strain-induced phase
separation) Also it was found that the addition of ions (K+ Ca+) has an effect on the
gelation behavior of such blend
Key words silk fibroin hydroxypropylcellulose hydrogel shear rheology
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
2
Relation between electric charges and beads formation on
Electro-spinning of Poly(vinyl alcohol)
Yosuke KADOMAE Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA
Department of Polymer Science and Engineering Yamagata University 4-3-16 Jonan Yonezawa 992-8510
TEL 0238-26-3058 FAX 0238-26-3411 Email kadomaeckpssyzyamagata-uacjp
Abstract We investigate formation of beads on electro-spinning by changing conductivity of poly
vinyl alcohol (PVA) aqueous solutions and spinning conditions such as applied voltage distance (L) between the tip of needle and the collector and humidity Electric conductivity of PVA aqueous solutions was controlled by changing amount of salt (NaCl)
From the results of experiments done by changing conductivity and spinning conditions we found that the beads formation is related to electric charges at the tip of sample Formation of beads is enhanced with increasing electric conductivity of PVA aqueous solutions Additionally in cases of changing the spinning conditions beads formation is suppressed at lower electric charges When the applied voltage changes to be same electric charge in respective distances between the tip of needle and the collector beads-less fibers are fabricated in all cases as shown in Fig1
Fig1 SEM images of electro-spun fibers at the same electric charge condition (a)75kV
and L=5cm (b) 9kV and L=10cm (c) 12kV and L=15cm (d) 14kV and L=20cm
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
3
Sensitivity of Low- and High-speed Spinning Process with Flow-Induced Crystallization Kinetics
Jang Ho Yun Dong Myeong Shin Joo Sung Lee Hyun Wook Jung
and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology
Center Korea University Seoul Korea
Recent issues of the spinning process are to investigate effect of crystallization (FIC) kinetics on the spinning dynamics Doufas et al (JNNFM 2000) and Kohler et al (J Macromol Sci-Phys 2005) predicted spinline deformation by employing their two-phase crystallinity models Regarding the FIC occurring on the spinline Joo et al (JNNFM 2002) simulated the nonisothermal spinline crystallization using two-dimensional model and Lee et al (JNNFM 2005) for the first time solved the transient responses of the low-speed spinning accompanied by FIC using a one-phase crystallinity model Shin et al (Korea-Australia Rheol J 2005 Rheol Acta 2006) also adopted this model to analyze the effect of the FIC on the spinning stability and neck-like deformation in high-speed spinning by linear stability method
However sensitivity of the spinning system has not been fully elucidated yet although this is an indispensable tool for the processability and product quality in industry In this study the sensitivity of both low- and high-speed spinning processes has been scrutinized by frequency response method measuring the amplitude ratio of output with respect to the infinitesimal sinusoidal disturbances in the linearized system (Jung et al Korea J Chem Eng 2004) In the low-speed spinning case there exists an optimal crystallinity region making the system the lowest sensitive to any disturbance In the high-speed case high inertia compensates for destabilizing effect by high crystallinity and makes the system generally less sensitive leading to the reduced resonance peaks by neck-like deformation Sensitivity results have closely been correlated with the previous ones by linear stability (Shin et al 2005 2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
4
Predicting permeability for fibrous porous media based on
micro-structure with direct simulation method
Jun Feng Wang Wook Ryol Hwang Shin Hyun Kang
School of Mechanical and Aerospace Engineering Gyeongsang National University South Korea
ABSTRACT
In this study a new finite element scheme is presented to investigate the permeability of fibrous porous media which is an important parameter in the resin transfer molding simulation A representative bi-periodic domain concept is introduced such that a single cell problem with a relatively small number of fiber filaments or fiber bundles may represent a large number of repeated structures of such a cell in the transversal planar flow through fiber arrays To use the regular rectangular mesh for the entire computation we employed a finite-element fictitious-domain method similar to the distributed Lagrangian multiplier method together with the rigid-ring description of the fiber The constraint for the bi-periodic domain is implemented by the mortar element method Examples of a single domain problem with one fiber 10 fibers and randomly distributed 100 fibers are investigated the normalized permeability shows approximately a uniform function of the fiber volume fraction which makes it possible to estimate the practical average permeability of fiber tows in several micro-meter scales The predicted results agree well with existing experimental data and numerical prediction in the literature In addition we present the permeability prediction for fiber bundles and investigate the effect of orientation on the permeability
The method we developed in this study is quite well suited for predicting the permeability of fibrous porous media and investigating the flow features in different micro-scale fiber architectures along with the inter-relationship between them Since the present scheme is based on the standard velocity-pressure formulation of the finite-element method it was also easily extended to the problem with non-Newtonian fluid medium In addition the present scheme was applied to three-dimensional problems with a tri-periodic unit cell In 3D cases the predicted permeability of porous media with regular packing fiber was compared with the results of other research
KEY WORDS Microstructure Finite element analysis Permeability Direct simulation Bi-periodic frame
Acknowledgement This work has been supported by the second stage BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
5
The effect of viscosity and flow rate on the droplet size and
formation pattern in T-shaped microchannel
Duwon Choi Sung Sik Lee Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
Tel 82-2-880-1579 E-mail tetra4646parancom
Abstract
It is important to characterize the size and formation pattern in order to manipulate
the small size (piconanoliter size) of droplets for chemical and biological applications Previously Garstecki et al investigated the size and formation pattern of micron-size droplets under low viscosity ratio condition In this study we conducted the experiments of micron-size droplets generation under wide range of viscosity ratio including above 1
This experiment was performed in a confined T-shaped microchannel made by soft lithography method Immiscible two liquids glycerol aqueous solution (dispersed flow) and corn oil (carrier flow) flow in the channel with rate ranging from 003ulmin to 5ulmin in each liquid flow We changed the viscosity ratio from 002 (DI water) to 28 (glycerol 90 in water) to understand the effect of viscosity on droplet size and formation pattern
We could obtain the maps of size and formation pattern as changing flow rate and viscosity ratio We expect that these maps help predict the size of droplets and their applications such as droplet based reaction (two droplets fusion) and generation of double emulsion
[1] P Garstecki M J Furestman H A Stone and G M White 2006 Labchip 5
437-446
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
6
Transient behaviors of immiscible polymer blends under varying flow
field
QUAN CHEN WEI YU CHIXING ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering Shanghai Jiao Tong University Shanghai 200240 P R China
One frequently used method on measuring thixotropy is to perform a loop test In
which changes in the structural level like the break-up and coalescence of the drops
cause measurable thixotropic behavior (Barnes HA (1997)) The flow field in our
experiment is the round trip (RT) test in which an additional opposite trip is added on
traditional thixotropic test The breakup and coalescence mechanics under such a flow
field is discussed here In addition a new model (Yu W and Zhou C (2006)) in which
breakup and coalescence is applied in our analysis
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
7
The effect of viscosity and elasticity on the DOD (Drop-On-Demand) inkjet drop formation
A Young Lee
Byoung Wook Jo Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1879
Email twinklesnuackr
Abstract Inkjet printing is familiar as a method of printing text and images onto substrates
such as paper In the last few years it has been explored as a way of printing electrical and optical devices with the use of specialty inks For a successful inkjet printing to be achieved in this area high resolution patternability is necessary Therefore it is essential to understand the mechanism of ink drop deformation and to reduce the satellite drop which can cause defect in printing
The breakup of viscoelastic jets has been studied by many researchers with a number of dilute and semidilute poly(ethylene oxide) solutions under the gravity Similarly the presence of small amounts of polymer in Newtonian solvents can cause a significant change of the drop-on-demand drop formation This study investigates the effect of viscosity and elasticity on the drop-on-demand drop formation through the use of Newtonian liquids and low viscosity elastic liquids The satellite drop produced by breakup of main drop is easily observed by Newtonian fluids Higher viscosity can suppress this satellite drop formation to some extent and the phenomena become significant when small amount of polymer is added To quantitatively characterize the behavior of drop deformation we compared jet retraction time and breakup time by employing jet stability graphs In jet stability graph the two critical jet speeds can suggest the relative jetting stability in terms of satellite drop generation Finally the effect of imposed pulse shape on drop formation is also studied
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
8
Dielectric Studies of Polymer Chain Dynamics in Polymer Blend
JunTakada HiroshiSasaki YoshiakiMatsushima AkiraKuriyama YumiMatsumiya
TadashiInoue HiroshiWatanabe
Toagosei CoLtd and Institute for Chemical ResearchKyoto University
We examined a relationship between polymer chain dynamics and phase separated
structure in polymer blends The samples used were blends of
polyisoprene(PIPMw=199times10 3 ) and poly-tert-butylstyrene(P-t-BS-HMw=700times10 3
P-t-BS-LMw=160times10 3 ) The blend ratio was PIPP-t-BS=82(wtwt) To discuss the
changes of polymer chain dynamics we investigated the dielectric loss ε rdquo of the blend
samples and pure PIP PIP has type-A dipoles that enable us to dielectrically observe
the global motion of PIP At 30 the global motion of PIP in the blend samples was
slower than that of pure PIP This result suggests that the PIP chains are entangled
with the P-t-BS chains ie mixed in P-t-BS phase and the entanglements retards the
global motion of PIP At 70 the global motion of PIP in blend samples became close
to that of pure PIP suggesting that the PIP chains are not well entangled with P-t-BS
chains at high temperature It has been known that PIPP-t-BS blends exhibit
LCST-type phase behavior Changes of the global motion of PIP in blend samples with
temperature is consistent with this phase behavior
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
9
Normal stress development under large amplitude oscillatory
shear flow
Jung Gun Nam Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email guns2snuackr
Abstract The dynamic response of viscoelastic fluids under large amplitude oscillatory shear (LAOS) has been a subject of long history In recent years there seem to be progresses in this field More advanced instrumentation and new concepts are emerging In the LAOS flow the analysis has been mostly focused on shear stress possibly due to the lack of accurate measurement of normal stress However the normal stress may become larger than shear stress at high strain amplitudes and there are good reasons we need to understand the normal stress behavior As the instrumentation advances it becomes more feasible to get reliable data and this field will be more challenging The purpose of this paper is to develop a research platform to analyze and thereby to understand the normal stress behavior of complex fluids under LAOS flow We take the Giesekus model as a representative constitutive model and investigate diverse responses of the model We define new dynamic properties corresponding to normal stresses in a similar way to define dynamic moduli from shear stress and examine their behavior with various analyzing tools Experimental data are also compared with model predictions Though it is not yet possible to compare all the predictions due to instrumental limitation the prediction fits well with the experimental data and we hope this study provide a useful framework for further understanding of the nonlinear behavior of complex fluids under LAOS flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
10
Nonlinear behavior of complex fluids under large amplitude
oscillatory shear and squeezing flow
Juha Hwang
Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1580
Email jindols79hotmailcom
Abstract
The purpose of this research is to figure out viscoelastic behavior under large amplitude oscillatory shear (LAOS) and squeezing flow To analyze this behavior we have applied following nonlinear constitutive equations Upper convected Maxwell Giesekus FENE-P Marrucci Leonov Larson and Pom-pom model We analyzed the simulation results by modulus Fourier transform and stress decomposition which distinguishes elastic from viscous contribution to total stress The simulation results were compared with experimental data in other literatures Most constitutive equations predict LAOS behavior qualitatively in shear flow while only Larson model predicts LAOS behavior in squeezing flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
11
Studies on micro-convections induced in a polymer solution heated from above Yasuhiro YAMADA Shinichi SAKURAI
Polymer Science amp Engineering Kyoto Institute of Technology Kyoto Japan
We have reported micro-convections induced by the Soret effect in a polystyrene (PS)dioctylphthalate (DOP) solution under a temperature gradient (heated from below) The Soret effect stands for the fact that the concentration gradient is induced under the applied temperature gradient When temperature gradient is formed in a PSDOP solution PS is accumulated in the cooler side (upper side) by the Soret effect Then the concentrated PS solution undergoes sedimentation because the density of PS is higher than DOP Since this event can take place and result in a convective motion in a considerably thin layer of the solution (say 01 mm thickness) we refer to this as ldquomicro-convectionrdquo If the solvent density is larger than polymer a micro-convection can be induced even when such a solution is heated from above To examine this speculation we conducted experiments on a PStricresylphosphate (TCP) solution heated from above Note that the density of the solvent (TCP) is higher than that of PS Densities are 098 117 and 105 (gcm2) for DOP TCP and PS respectively
The samples used were PS (Mw=200k and MwMn=105) as a solute and TCP as a solvent The weight compositions are in the range of 01999 ~ 50950 The polymer solution was confined in a 05mm thickness layer Temperatures at the top and bottom plates Ttop and Tbot respectively were controlled independently by circulating temperature-regulated water being Ttop and Tbot at 35 and 65 respectively We observed such the polymer solution under a phase-contrast microscope As a result it was found that convection was generated in PSTCP solutions even when heated from above instead of being heated from below Fig 1 shows a typical result of a phase-contrast microscopic observation for the PSTCP sample (50950 composition) heated from below (a) and from above (b) In addition we analyzed dark meshes of convection to obtain brightness of the dark meshes based on which temporal changes in convection activity were examined In Fig2 were shown temporal changes in the brightness of the dark mesh for the PSTCP sample (50950 composition) Some oscillations were found and the brightness finally reached an asymptotic value It is interesting to note that a similar behavior was seen for the case of a PSDOP solution heated from bottom although the direction of the energy input is opposed
---------------------------------------------------------------------------------------------------------------- Corresponding author e-mail d2jyasmailgoonejp TEL 075-724-7864 FAX 075-724-7800
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
12
Development of a mixed-flow rheometer
Jae Hee Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email exodus55snuackr
Abstract This paper is concerned with the development of a mixed-flow rheometer for
determining the viscosity of a highly viscous filled viscoplastic fluid Recently there has been a renewal of interest in mixed-flow of viscoelastic fluid It is difficult to characterize the viscoelastic materials using conventional rheometer such as capillary rotational and compressional rheometers
In this study we develop a new rheometer for analysis of mixed-flow which is the combination of shear and compression mode This rheometer is designed for investigating the different microstructural rearrangement processes by the combination of two-deformation modes It is important to understand the combined-mode within an industrial quality control environment
In this presentation we will summarize the recent method for determination of the properties of viscoelastic systems under mixed-flow and provide a comprehensive mathematical theory for the interpretation of experimental data from the mixed-flow rheometer considering the influence of fluid inertia Also a series of experiments were carried out on a number of viscoelastic systems to confirm the theory
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
13
Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA Tadamine KIMU Hideshige SUZUKI Akihiro NISHIOKA
Tomonori KODA and Susumu IKEDA Department of Polymer Science and Engineering Yamagata University
Ikeda laboratry Yonezawa 992-8510 Japan E-mail dmx13313dipyzyamagata-uacjp
The purpose of this study is to clarify Ferroelectricity and Crystallization in
Poly(vinylidene fluoride)clay nanocomposites The ferroelectoricity in PVDFclay nanocomposites have been examined by measuring the D-E hysteresis loops The composites were also characterized by XRD DSC and TEM The nanocomposites were prepared by using melt compounding method This compounding was carried out by using the Twin Screw Extruder (TECHNOVEL Co Ltd model KZW-30 LD = 45) All samples for measurement were produced by hot press method at 200oC from dried pellet samples
As a result we found that the ferroelectricity can be observed in non-stretched PVDFclay nanocomposites films The PVDF crystal structure in its nanocomposites was similar to β form This results means that blending small amount of nano is one of the way to induce ferroelecticity of PVDF without stretching To clarify the mechanism of the induction ferroelecticity we have estimated lattice spacing of a clay surface by XRD The spacing between negatively charged oxygens on a clay surface is about 257Å which is almost the same spacing of monomer unit of PVDF in all trans chain conformation PVDF monomer on negatively charged clay surface has a permanent electrical dipole moment PVDF crystallites are epitaxially grown up on the clay surface in accordance with surface lattice structure
Acknowledgement We would like to thank for the cooperation of Prof KHAhn and all members of his
Laboratory in Seoul National University (SNU) Korea We would like to thank for providing us with TEM photos of our samples I would also like to thank Mr Namkung Mr Kim and Prof KH Ahn for their valuable comments suggestions support during my stay in Seoul National University (SNU)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
14
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Poster Presentationpage
P1 Direct numerical simulation of mold filling process with (elliptic) particle filled fluidsShin Hyun Kang (Gyeongsang Natl Univ) 32
P2 Capillary spreading of drops of particulate suspensions on the solid substrateHyun Jun Jung (Gyeongsang Natl Univ) 33
P3 Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting ProcessDong Myeong Shin (Korea Univ) 34
P4 Flow Instabilities in ForwardReverse Roll Coating ProcessesSang Kwon Han (Korea Univ) 35
P5 Optimal Die InternalExternal Designs for Patch Slot CoatingSeo Hoon Shim (Korea Univ) 36
P6 Dynamics of DNA tumbling in shear to rotational mixed flowJeong Yong Lee (Korea Univ) 37
P7 Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi Kawakita (Tokyo Univ of A amp T) 38
P8 Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinningof Poly (ethylene terephthalate)
Hitoshi Hotchi (Tokyo Univ of A amp T) 39
P9 Rheology of semi-dilute solution of Ecoli DNA
Taro Kinoshita (Tokyo Univ of A amp T) 40
P10 Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki Moriya (Tokyo Univ of A amp T) 41
P11 Magnetic Orientation of Microdomains in Block Copolymer
Akifumi Yasui (Kyoto Inst Technol) 42
P12Microphase-Separated Structure and Molecular mobility of shorter end-block chain inAsymmetric Poly(methyl acrylate)-block -polystyrene-block -poly(methyl acrylate)Triblock Copolymer
Junji Fukuhara (Kyoto Inst Technol) 43
P13 High Frequency Dielectric Relaxation Behavior of Aqueous Solutions of Poly(vinylsulfate) Salts with Various Counterions
Yuichi Satokawa (Osaka Univ) 44
P14 Effects of Hydrogen-Bonds on the Dynamics of BenzylAlcohol
Shogo Nobukawa (Osaka Univ) 45
P15 High Frequency Dielectric Relaxation Behavior of Aqueous Solution ofPoly(Sulfobetaine)s
Yousuke Ono (Osaka Univ) 46
P16 Polymer conformation under fast flow
Tatsuya Iwamoto (Kyoto Univ) 47
P17 Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige (Kyoto Univ) 48
Rheological properties of novel silk fiberpoly (ε-caprolactone)
biocomposites Wei Li Xiuying Qiao Kang Sun
(State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China)
Abstract In this study novel silk fiber (SF) reinforced poly (ε-caprolactone) (PCL)
biocomposites have been fabricated and their rheological properties have been studied The novel biocomposites with appropriate mechanical properties slow degradation rate and good biocompatibility are expected to be used as internal fixation vehicles for bone However as a kind of biomaterials the composites must be sterilized before being embedded into human bodies So the electron beam irradiation treatment is used to sterilize the composites
Rheological analysis is used to study the rheological properties of the SFPCL biocomposites before and after irradiation A small amplitude dynamic oscillation test is selected and the linear viscoelastic range complex viscosity storage modulus and loss modulus are obtained The effects of fiber content and irradiation dose on the biocomposites are discussed
The silk fibers play an important role as reinforcements in improving the viscoelasitic properties of SFPCL composites Both viscosity and modulus increase as the fiber content increases and the reinforcement effect is more obviously at low frequency range than at high frequency range When adding into fiber the storage modulus reaches a plateau at low frequency indicating that when fiber content increases the interaction between fiber and fiber becomes dominant An interconnected structure between fiber and fiber is formed which requires higher shear stress and longer relaxation time for the composites to flow The increase of storage modulus is quicker than loss modulus The fiber addition changes the rheological behavior of composites from a viscous performance to an elastic-like performance However from the plots of storage modulus versus loss modulus of composites the interfacial interaction between fiber and matrix is not very strong
After being irradiated the viscosity and modulus of composites decrease as the irradiation dose increases at high frequency range and reach a maximum at a dose of 150KGy at low frequency range The plateau of storage modulus shifts to higher frequency as the irradiation dose increasing indicating that the interaction between fiber and matrix is improved by irradiation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
1
Rheological characterization of hydrogel formed by the
blend of silk fibroin and hydroxypropylcellulose
Zuguang Gong Jinrong Yao Zhengzhong Shao
The Key Laboratory of Molecular Engineering of Polymer and Department of
Macromolecular Science Fudan University Shanghai 200433 China
Silk fibroin as the dominant protein in the raw Bombyx mori silk has a bright
prospect in biomedical application for its excellent morphological plasticity and
biocompatibility Hydroxypopylcellulose as one kind of water soluble cellulose
derivatives is a biocompatible polymer used for a wide range of applications in the food
pharmaceutical and cosmetic industries In our research the hydrogels formed by silk
fibroin and hydroxypropylcellulose blends were investigated using rheology We
focused on the concentration and component ratio dependence of the gelation time and
the elastic modulus of the hydrogel while the influence of shear (shear strain and
oscillatory frequency) on the dynamics of gelation process was investigated as silk
fibroin was highly shear-sensitive in aqueous solution (in nature the silkworms
conversion of the liquid dope to the solid fibre occurs through a strain-induced phase
separation) Also it was found that the addition of ions (K+ Ca+) has an effect on the
gelation behavior of such blend
Key words silk fibroin hydroxypropylcellulose hydrogel shear rheology
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
2
Relation between electric charges and beads formation on
Electro-spinning of Poly(vinyl alcohol)
Yosuke KADOMAE Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA
Department of Polymer Science and Engineering Yamagata University 4-3-16 Jonan Yonezawa 992-8510
TEL 0238-26-3058 FAX 0238-26-3411 Email kadomaeckpssyzyamagata-uacjp
Abstract We investigate formation of beads on electro-spinning by changing conductivity of poly
vinyl alcohol (PVA) aqueous solutions and spinning conditions such as applied voltage distance (L) between the tip of needle and the collector and humidity Electric conductivity of PVA aqueous solutions was controlled by changing amount of salt (NaCl)
From the results of experiments done by changing conductivity and spinning conditions we found that the beads formation is related to electric charges at the tip of sample Formation of beads is enhanced with increasing electric conductivity of PVA aqueous solutions Additionally in cases of changing the spinning conditions beads formation is suppressed at lower electric charges When the applied voltage changes to be same electric charge in respective distances between the tip of needle and the collector beads-less fibers are fabricated in all cases as shown in Fig1
Fig1 SEM images of electro-spun fibers at the same electric charge condition (a)75kV
and L=5cm (b) 9kV and L=10cm (c) 12kV and L=15cm (d) 14kV and L=20cm
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
3
Sensitivity of Low- and High-speed Spinning Process with Flow-Induced Crystallization Kinetics
Jang Ho Yun Dong Myeong Shin Joo Sung Lee Hyun Wook Jung
and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology
Center Korea University Seoul Korea
Recent issues of the spinning process are to investigate effect of crystallization (FIC) kinetics on the spinning dynamics Doufas et al (JNNFM 2000) and Kohler et al (J Macromol Sci-Phys 2005) predicted spinline deformation by employing their two-phase crystallinity models Regarding the FIC occurring on the spinline Joo et al (JNNFM 2002) simulated the nonisothermal spinline crystallization using two-dimensional model and Lee et al (JNNFM 2005) for the first time solved the transient responses of the low-speed spinning accompanied by FIC using a one-phase crystallinity model Shin et al (Korea-Australia Rheol J 2005 Rheol Acta 2006) also adopted this model to analyze the effect of the FIC on the spinning stability and neck-like deformation in high-speed spinning by linear stability method
However sensitivity of the spinning system has not been fully elucidated yet although this is an indispensable tool for the processability and product quality in industry In this study the sensitivity of both low- and high-speed spinning processes has been scrutinized by frequency response method measuring the amplitude ratio of output with respect to the infinitesimal sinusoidal disturbances in the linearized system (Jung et al Korea J Chem Eng 2004) In the low-speed spinning case there exists an optimal crystallinity region making the system the lowest sensitive to any disturbance In the high-speed case high inertia compensates for destabilizing effect by high crystallinity and makes the system generally less sensitive leading to the reduced resonance peaks by neck-like deformation Sensitivity results have closely been correlated with the previous ones by linear stability (Shin et al 2005 2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
4
Predicting permeability for fibrous porous media based on
micro-structure with direct simulation method
Jun Feng Wang Wook Ryol Hwang Shin Hyun Kang
School of Mechanical and Aerospace Engineering Gyeongsang National University South Korea
ABSTRACT
In this study a new finite element scheme is presented to investigate the permeability of fibrous porous media which is an important parameter in the resin transfer molding simulation A representative bi-periodic domain concept is introduced such that a single cell problem with a relatively small number of fiber filaments or fiber bundles may represent a large number of repeated structures of such a cell in the transversal planar flow through fiber arrays To use the regular rectangular mesh for the entire computation we employed a finite-element fictitious-domain method similar to the distributed Lagrangian multiplier method together with the rigid-ring description of the fiber The constraint for the bi-periodic domain is implemented by the mortar element method Examples of a single domain problem with one fiber 10 fibers and randomly distributed 100 fibers are investigated the normalized permeability shows approximately a uniform function of the fiber volume fraction which makes it possible to estimate the practical average permeability of fiber tows in several micro-meter scales The predicted results agree well with existing experimental data and numerical prediction in the literature In addition we present the permeability prediction for fiber bundles and investigate the effect of orientation on the permeability
The method we developed in this study is quite well suited for predicting the permeability of fibrous porous media and investigating the flow features in different micro-scale fiber architectures along with the inter-relationship between them Since the present scheme is based on the standard velocity-pressure formulation of the finite-element method it was also easily extended to the problem with non-Newtonian fluid medium In addition the present scheme was applied to three-dimensional problems with a tri-periodic unit cell In 3D cases the predicted permeability of porous media with regular packing fiber was compared with the results of other research
KEY WORDS Microstructure Finite element analysis Permeability Direct simulation Bi-periodic frame
Acknowledgement This work has been supported by the second stage BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
5
The effect of viscosity and flow rate on the droplet size and
formation pattern in T-shaped microchannel
Duwon Choi Sung Sik Lee Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
Tel 82-2-880-1579 E-mail tetra4646parancom
Abstract
It is important to characterize the size and formation pattern in order to manipulate
the small size (piconanoliter size) of droplets for chemical and biological applications Previously Garstecki et al investigated the size and formation pattern of micron-size droplets under low viscosity ratio condition In this study we conducted the experiments of micron-size droplets generation under wide range of viscosity ratio including above 1
This experiment was performed in a confined T-shaped microchannel made by soft lithography method Immiscible two liquids glycerol aqueous solution (dispersed flow) and corn oil (carrier flow) flow in the channel with rate ranging from 003ulmin to 5ulmin in each liquid flow We changed the viscosity ratio from 002 (DI water) to 28 (glycerol 90 in water) to understand the effect of viscosity on droplet size and formation pattern
We could obtain the maps of size and formation pattern as changing flow rate and viscosity ratio We expect that these maps help predict the size of droplets and their applications such as droplet based reaction (two droplets fusion) and generation of double emulsion
[1] P Garstecki M J Furestman H A Stone and G M White 2006 Labchip 5
437-446
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
6
Transient behaviors of immiscible polymer blends under varying flow
field
QUAN CHEN WEI YU CHIXING ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering Shanghai Jiao Tong University Shanghai 200240 P R China
One frequently used method on measuring thixotropy is to perform a loop test In
which changes in the structural level like the break-up and coalescence of the drops
cause measurable thixotropic behavior (Barnes HA (1997)) The flow field in our
experiment is the round trip (RT) test in which an additional opposite trip is added on
traditional thixotropic test The breakup and coalescence mechanics under such a flow
field is discussed here In addition a new model (Yu W and Zhou C (2006)) in which
breakup and coalescence is applied in our analysis
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
7
The effect of viscosity and elasticity on the DOD (Drop-On-Demand) inkjet drop formation
A Young Lee
Byoung Wook Jo Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1879
Email twinklesnuackr
Abstract Inkjet printing is familiar as a method of printing text and images onto substrates
such as paper In the last few years it has been explored as a way of printing electrical and optical devices with the use of specialty inks For a successful inkjet printing to be achieved in this area high resolution patternability is necessary Therefore it is essential to understand the mechanism of ink drop deformation and to reduce the satellite drop which can cause defect in printing
The breakup of viscoelastic jets has been studied by many researchers with a number of dilute and semidilute poly(ethylene oxide) solutions under the gravity Similarly the presence of small amounts of polymer in Newtonian solvents can cause a significant change of the drop-on-demand drop formation This study investigates the effect of viscosity and elasticity on the drop-on-demand drop formation through the use of Newtonian liquids and low viscosity elastic liquids The satellite drop produced by breakup of main drop is easily observed by Newtonian fluids Higher viscosity can suppress this satellite drop formation to some extent and the phenomena become significant when small amount of polymer is added To quantitatively characterize the behavior of drop deformation we compared jet retraction time and breakup time by employing jet stability graphs In jet stability graph the two critical jet speeds can suggest the relative jetting stability in terms of satellite drop generation Finally the effect of imposed pulse shape on drop formation is also studied
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
8
Dielectric Studies of Polymer Chain Dynamics in Polymer Blend
JunTakada HiroshiSasaki YoshiakiMatsushima AkiraKuriyama YumiMatsumiya
TadashiInoue HiroshiWatanabe
Toagosei CoLtd and Institute for Chemical ResearchKyoto University
We examined a relationship between polymer chain dynamics and phase separated
structure in polymer blends The samples used were blends of
polyisoprene(PIPMw=199times10 3 ) and poly-tert-butylstyrene(P-t-BS-HMw=700times10 3
P-t-BS-LMw=160times10 3 ) The blend ratio was PIPP-t-BS=82(wtwt) To discuss the
changes of polymer chain dynamics we investigated the dielectric loss ε rdquo of the blend
samples and pure PIP PIP has type-A dipoles that enable us to dielectrically observe
the global motion of PIP At 30 the global motion of PIP in the blend samples was
slower than that of pure PIP This result suggests that the PIP chains are entangled
with the P-t-BS chains ie mixed in P-t-BS phase and the entanglements retards the
global motion of PIP At 70 the global motion of PIP in blend samples became close
to that of pure PIP suggesting that the PIP chains are not well entangled with P-t-BS
chains at high temperature It has been known that PIPP-t-BS blends exhibit
LCST-type phase behavior Changes of the global motion of PIP in blend samples with
temperature is consistent with this phase behavior
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
9
Normal stress development under large amplitude oscillatory
shear flow
Jung Gun Nam Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email guns2snuackr
Abstract The dynamic response of viscoelastic fluids under large amplitude oscillatory shear (LAOS) has been a subject of long history In recent years there seem to be progresses in this field More advanced instrumentation and new concepts are emerging In the LAOS flow the analysis has been mostly focused on shear stress possibly due to the lack of accurate measurement of normal stress However the normal stress may become larger than shear stress at high strain amplitudes and there are good reasons we need to understand the normal stress behavior As the instrumentation advances it becomes more feasible to get reliable data and this field will be more challenging The purpose of this paper is to develop a research platform to analyze and thereby to understand the normal stress behavior of complex fluids under LAOS flow We take the Giesekus model as a representative constitutive model and investigate diverse responses of the model We define new dynamic properties corresponding to normal stresses in a similar way to define dynamic moduli from shear stress and examine their behavior with various analyzing tools Experimental data are also compared with model predictions Though it is not yet possible to compare all the predictions due to instrumental limitation the prediction fits well with the experimental data and we hope this study provide a useful framework for further understanding of the nonlinear behavior of complex fluids under LAOS flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
10
Nonlinear behavior of complex fluids under large amplitude
oscillatory shear and squeezing flow
Juha Hwang
Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1580
Email jindols79hotmailcom
Abstract
The purpose of this research is to figure out viscoelastic behavior under large amplitude oscillatory shear (LAOS) and squeezing flow To analyze this behavior we have applied following nonlinear constitutive equations Upper convected Maxwell Giesekus FENE-P Marrucci Leonov Larson and Pom-pom model We analyzed the simulation results by modulus Fourier transform and stress decomposition which distinguishes elastic from viscous contribution to total stress The simulation results were compared with experimental data in other literatures Most constitutive equations predict LAOS behavior qualitatively in shear flow while only Larson model predicts LAOS behavior in squeezing flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
11
Studies on micro-convections induced in a polymer solution heated from above Yasuhiro YAMADA Shinichi SAKURAI
Polymer Science amp Engineering Kyoto Institute of Technology Kyoto Japan
We have reported micro-convections induced by the Soret effect in a polystyrene (PS)dioctylphthalate (DOP) solution under a temperature gradient (heated from below) The Soret effect stands for the fact that the concentration gradient is induced under the applied temperature gradient When temperature gradient is formed in a PSDOP solution PS is accumulated in the cooler side (upper side) by the Soret effect Then the concentrated PS solution undergoes sedimentation because the density of PS is higher than DOP Since this event can take place and result in a convective motion in a considerably thin layer of the solution (say 01 mm thickness) we refer to this as ldquomicro-convectionrdquo If the solvent density is larger than polymer a micro-convection can be induced even when such a solution is heated from above To examine this speculation we conducted experiments on a PStricresylphosphate (TCP) solution heated from above Note that the density of the solvent (TCP) is higher than that of PS Densities are 098 117 and 105 (gcm2) for DOP TCP and PS respectively
The samples used were PS (Mw=200k and MwMn=105) as a solute and TCP as a solvent The weight compositions are in the range of 01999 ~ 50950 The polymer solution was confined in a 05mm thickness layer Temperatures at the top and bottom plates Ttop and Tbot respectively were controlled independently by circulating temperature-regulated water being Ttop and Tbot at 35 and 65 respectively We observed such the polymer solution under a phase-contrast microscope As a result it was found that convection was generated in PSTCP solutions even when heated from above instead of being heated from below Fig 1 shows a typical result of a phase-contrast microscopic observation for the PSTCP sample (50950 composition) heated from below (a) and from above (b) In addition we analyzed dark meshes of convection to obtain brightness of the dark meshes based on which temporal changes in convection activity were examined In Fig2 were shown temporal changes in the brightness of the dark mesh for the PSTCP sample (50950 composition) Some oscillations were found and the brightness finally reached an asymptotic value It is interesting to note that a similar behavior was seen for the case of a PSDOP solution heated from bottom although the direction of the energy input is opposed
---------------------------------------------------------------------------------------------------------------- Corresponding author e-mail d2jyasmailgoonejp TEL 075-724-7864 FAX 075-724-7800
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
12
Development of a mixed-flow rheometer
Jae Hee Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email exodus55snuackr
Abstract This paper is concerned with the development of a mixed-flow rheometer for
determining the viscosity of a highly viscous filled viscoplastic fluid Recently there has been a renewal of interest in mixed-flow of viscoelastic fluid It is difficult to characterize the viscoelastic materials using conventional rheometer such as capillary rotational and compressional rheometers
In this study we develop a new rheometer for analysis of mixed-flow which is the combination of shear and compression mode This rheometer is designed for investigating the different microstructural rearrangement processes by the combination of two-deformation modes It is important to understand the combined-mode within an industrial quality control environment
In this presentation we will summarize the recent method for determination of the properties of viscoelastic systems under mixed-flow and provide a comprehensive mathematical theory for the interpretation of experimental data from the mixed-flow rheometer considering the influence of fluid inertia Also a series of experiments were carried out on a number of viscoelastic systems to confirm the theory
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
13
Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA Tadamine KIMU Hideshige SUZUKI Akihiro NISHIOKA
Tomonori KODA and Susumu IKEDA Department of Polymer Science and Engineering Yamagata University
Ikeda laboratry Yonezawa 992-8510 Japan E-mail dmx13313dipyzyamagata-uacjp
The purpose of this study is to clarify Ferroelectricity and Crystallization in
Poly(vinylidene fluoride)clay nanocomposites The ferroelectoricity in PVDFclay nanocomposites have been examined by measuring the D-E hysteresis loops The composites were also characterized by XRD DSC and TEM The nanocomposites were prepared by using melt compounding method This compounding was carried out by using the Twin Screw Extruder (TECHNOVEL Co Ltd model KZW-30 LD = 45) All samples for measurement were produced by hot press method at 200oC from dried pellet samples
As a result we found that the ferroelectricity can be observed in non-stretched PVDFclay nanocomposites films The PVDF crystal structure in its nanocomposites was similar to β form This results means that blending small amount of nano is one of the way to induce ferroelecticity of PVDF without stretching To clarify the mechanism of the induction ferroelecticity we have estimated lattice spacing of a clay surface by XRD The spacing between negatively charged oxygens on a clay surface is about 257Å which is almost the same spacing of monomer unit of PVDF in all trans chain conformation PVDF monomer on negatively charged clay surface has a permanent electrical dipole moment PVDF crystallites are epitaxially grown up on the clay surface in accordance with surface lattice structure
Acknowledgement We would like to thank for the cooperation of Prof KHAhn and all members of his
Laboratory in Seoul National University (SNU) Korea We would like to thank for providing us with TEM photos of our samples I would also like to thank Mr Namkung Mr Kim and Prof KH Ahn for their valuable comments suggestions support during my stay in Seoul National University (SNU)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
14
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Rheological properties of novel silk fiberpoly (ε-caprolactone)
biocomposites Wei Li Xiuying Qiao Kang Sun
(State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China)
Abstract In this study novel silk fiber (SF) reinforced poly (ε-caprolactone) (PCL)
biocomposites have been fabricated and their rheological properties have been studied The novel biocomposites with appropriate mechanical properties slow degradation rate and good biocompatibility are expected to be used as internal fixation vehicles for bone However as a kind of biomaterials the composites must be sterilized before being embedded into human bodies So the electron beam irradiation treatment is used to sterilize the composites
Rheological analysis is used to study the rheological properties of the SFPCL biocomposites before and after irradiation A small amplitude dynamic oscillation test is selected and the linear viscoelastic range complex viscosity storage modulus and loss modulus are obtained The effects of fiber content and irradiation dose on the biocomposites are discussed
The silk fibers play an important role as reinforcements in improving the viscoelasitic properties of SFPCL composites Both viscosity and modulus increase as the fiber content increases and the reinforcement effect is more obviously at low frequency range than at high frequency range When adding into fiber the storage modulus reaches a plateau at low frequency indicating that when fiber content increases the interaction between fiber and fiber becomes dominant An interconnected structure between fiber and fiber is formed which requires higher shear stress and longer relaxation time for the composites to flow The increase of storage modulus is quicker than loss modulus The fiber addition changes the rheological behavior of composites from a viscous performance to an elastic-like performance However from the plots of storage modulus versus loss modulus of composites the interfacial interaction between fiber and matrix is not very strong
After being irradiated the viscosity and modulus of composites decrease as the irradiation dose increases at high frequency range and reach a maximum at a dose of 150KGy at low frequency range The plateau of storage modulus shifts to higher frequency as the irradiation dose increasing indicating that the interaction between fiber and matrix is improved by irradiation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
1
Rheological characterization of hydrogel formed by the
blend of silk fibroin and hydroxypropylcellulose
Zuguang Gong Jinrong Yao Zhengzhong Shao
The Key Laboratory of Molecular Engineering of Polymer and Department of
Macromolecular Science Fudan University Shanghai 200433 China
Silk fibroin as the dominant protein in the raw Bombyx mori silk has a bright
prospect in biomedical application for its excellent morphological plasticity and
biocompatibility Hydroxypopylcellulose as one kind of water soluble cellulose
derivatives is a biocompatible polymer used for a wide range of applications in the food
pharmaceutical and cosmetic industries In our research the hydrogels formed by silk
fibroin and hydroxypropylcellulose blends were investigated using rheology We
focused on the concentration and component ratio dependence of the gelation time and
the elastic modulus of the hydrogel while the influence of shear (shear strain and
oscillatory frequency) on the dynamics of gelation process was investigated as silk
fibroin was highly shear-sensitive in aqueous solution (in nature the silkworms
conversion of the liquid dope to the solid fibre occurs through a strain-induced phase
separation) Also it was found that the addition of ions (K+ Ca+) has an effect on the
gelation behavior of such blend
Key words silk fibroin hydroxypropylcellulose hydrogel shear rheology
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
2
Relation between electric charges and beads formation on
Electro-spinning of Poly(vinyl alcohol)
Yosuke KADOMAE Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA
Department of Polymer Science and Engineering Yamagata University 4-3-16 Jonan Yonezawa 992-8510
TEL 0238-26-3058 FAX 0238-26-3411 Email kadomaeckpssyzyamagata-uacjp
Abstract We investigate formation of beads on electro-spinning by changing conductivity of poly
vinyl alcohol (PVA) aqueous solutions and spinning conditions such as applied voltage distance (L) between the tip of needle and the collector and humidity Electric conductivity of PVA aqueous solutions was controlled by changing amount of salt (NaCl)
From the results of experiments done by changing conductivity and spinning conditions we found that the beads formation is related to electric charges at the tip of sample Formation of beads is enhanced with increasing electric conductivity of PVA aqueous solutions Additionally in cases of changing the spinning conditions beads formation is suppressed at lower electric charges When the applied voltage changes to be same electric charge in respective distances between the tip of needle and the collector beads-less fibers are fabricated in all cases as shown in Fig1
Fig1 SEM images of electro-spun fibers at the same electric charge condition (a)75kV
and L=5cm (b) 9kV and L=10cm (c) 12kV and L=15cm (d) 14kV and L=20cm
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
3
Sensitivity of Low- and High-speed Spinning Process with Flow-Induced Crystallization Kinetics
Jang Ho Yun Dong Myeong Shin Joo Sung Lee Hyun Wook Jung
and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology
Center Korea University Seoul Korea
Recent issues of the spinning process are to investigate effect of crystallization (FIC) kinetics on the spinning dynamics Doufas et al (JNNFM 2000) and Kohler et al (J Macromol Sci-Phys 2005) predicted spinline deformation by employing their two-phase crystallinity models Regarding the FIC occurring on the spinline Joo et al (JNNFM 2002) simulated the nonisothermal spinline crystallization using two-dimensional model and Lee et al (JNNFM 2005) for the first time solved the transient responses of the low-speed spinning accompanied by FIC using a one-phase crystallinity model Shin et al (Korea-Australia Rheol J 2005 Rheol Acta 2006) also adopted this model to analyze the effect of the FIC on the spinning stability and neck-like deformation in high-speed spinning by linear stability method
However sensitivity of the spinning system has not been fully elucidated yet although this is an indispensable tool for the processability and product quality in industry In this study the sensitivity of both low- and high-speed spinning processes has been scrutinized by frequency response method measuring the amplitude ratio of output with respect to the infinitesimal sinusoidal disturbances in the linearized system (Jung et al Korea J Chem Eng 2004) In the low-speed spinning case there exists an optimal crystallinity region making the system the lowest sensitive to any disturbance In the high-speed case high inertia compensates for destabilizing effect by high crystallinity and makes the system generally less sensitive leading to the reduced resonance peaks by neck-like deformation Sensitivity results have closely been correlated with the previous ones by linear stability (Shin et al 2005 2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
4
Predicting permeability for fibrous porous media based on
micro-structure with direct simulation method
Jun Feng Wang Wook Ryol Hwang Shin Hyun Kang
School of Mechanical and Aerospace Engineering Gyeongsang National University South Korea
ABSTRACT
In this study a new finite element scheme is presented to investigate the permeability of fibrous porous media which is an important parameter in the resin transfer molding simulation A representative bi-periodic domain concept is introduced such that a single cell problem with a relatively small number of fiber filaments or fiber bundles may represent a large number of repeated structures of such a cell in the transversal planar flow through fiber arrays To use the regular rectangular mesh for the entire computation we employed a finite-element fictitious-domain method similar to the distributed Lagrangian multiplier method together with the rigid-ring description of the fiber The constraint for the bi-periodic domain is implemented by the mortar element method Examples of a single domain problem with one fiber 10 fibers and randomly distributed 100 fibers are investigated the normalized permeability shows approximately a uniform function of the fiber volume fraction which makes it possible to estimate the practical average permeability of fiber tows in several micro-meter scales The predicted results agree well with existing experimental data and numerical prediction in the literature In addition we present the permeability prediction for fiber bundles and investigate the effect of orientation on the permeability
The method we developed in this study is quite well suited for predicting the permeability of fibrous porous media and investigating the flow features in different micro-scale fiber architectures along with the inter-relationship between them Since the present scheme is based on the standard velocity-pressure formulation of the finite-element method it was also easily extended to the problem with non-Newtonian fluid medium In addition the present scheme was applied to three-dimensional problems with a tri-periodic unit cell In 3D cases the predicted permeability of porous media with regular packing fiber was compared with the results of other research
KEY WORDS Microstructure Finite element analysis Permeability Direct simulation Bi-periodic frame
Acknowledgement This work has been supported by the second stage BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
5
The effect of viscosity and flow rate on the droplet size and
formation pattern in T-shaped microchannel
Duwon Choi Sung Sik Lee Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
Tel 82-2-880-1579 E-mail tetra4646parancom
Abstract
It is important to characterize the size and formation pattern in order to manipulate
the small size (piconanoliter size) of droplets for chemical and biological applications Previously Garstecki et al investigated the size and formation pattern of micron-size droplets under low viscosity ratio condition In this study we conducted the experiments of micron-size droplets generation under wide range of viscosity ratio including above 1
This experiment was performed in a confined T-shaped microchannel made by soft lithography method Immiscible two liquids glycerol aqueous solution (dispersed flow) and corn oil (carrier flow) flow in the channel with rate ranging from 003ulmin to 5ulmin in each liquid flow We changed the viscosity ratio from 002 (DI water) to 28 (glycerol 90 in water) to understand the effect of viscosity on droplet size and formation pattern
We could obtain the maps of size and formation pattern as changing flow rate and viscosity ratio We expect that these maps help predict the size of droplets and their applications such as droplet based reaction (two droplets fusion) and generation of double emulsion
[1] P Garstecki M J Furestman H A Stone and G M White 2006 Labchip 5
437-446
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
6
Transient behaviors of immiscible polymer blends under varying flow
field
QUAN CHEN WEI YU CHIXING ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering Shanghai Jiao Tong University Shanghai 200240 P R China
One frequently used method on measuring thixotropy is to perform a loop test In
which changes in the structural level like the break-up and coalescence of the drops
cause measurable thixotropic behavior (Barnes HA (1997)) The flow field in our
experiment is the round trip (RT) test in which an additional opposite trip is added on
traditional thixotropic test The breakup and coalescence mechanics under such a flow
field is discussed here In addition a new model (Yu W and Zhou C (2006)) in which
breakup and coalescence is applied in our analysis
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
7
The effect of viscosity and elasticity on the DOD (Drop-On-Demand) inkjet drop formation
A Young Lee
Byoung Wook Jo Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1879
Email twinklesnuackr
Abstract Inkjet printing is familiar as a method of printing text and images onto substrates
such as paper In the last few years it has been explored as a way of printing electrical and optical devices with the use of specialty inks For a successful inkjet printing to be achieved in this area high resolution patternability is necessary Therefore it is essential to understand the mechanism of ink drop deformation and to reduce the satellite drop which can cause defect in printing
The breakup of viscoelastic jets has been studied by many researchers with a number of dilute and semidilute poly(ethylene oxide) solutions under the gravity Similarly the presence of small amounts of polymer in Newtonian solvents can cause a significant change of the drop-on-demand drop formation This study investigates the effect of viscosity and elasticity on the drop-on-demand drop formation through the use of Newtonian liquids and low viscosity elastic liquids The satellite drop produced by breakup of main drop is easily observed by Newtonian fluids Higher viscosity can suppress this satellite drop formation to some extent and the phenomena become significant when small amount of polymer is added To quantitatively characterize the behavior of drop deformation we compared jet retraction time and breakup time by employing jet stability graphs In jet stability graph the two critical jet speeds can suggest the relative jetting stability in terms of satellite drop generation Finally the effect of imposed pulse shape on drop formation is also studied
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
8
Dielectric Studies of Polymer Chain Dynamics in Polymer Blend
JunTakada HiroshiSasaki YoshiakiMatsushima AkiraKuriyama YumiMatsumiya
TadashiInoue HiroshiWatanabe
Toagosei CoLtd and Institute for Chemical ResearchKyoto University
We examined a relationship between polymer chain dynamics and phase separated
structure in polymer blends The samples used were blends of
polyisoprene(PIPMw=199times10 3 ) and poly-tert-butylstyrene(P-t-BS-HMw=700times10 3
P-t-BS-LMw=160times10 3 ) The blend ratio was PIPP-t-BS=82(wtwt) To discuss the
changes of polymer chain dynamics we investigated the dielectric loss ε rdquo of the blend
samples and pure PIP PIP has type-A dipoles that enable us to dielectrically observe
the global motion of PIP At 30 the global motion of PIP in the blend samples was
slower than that of pure PIP This result suggests that the PIP chains are entangled
with the P-t-BS chains ie mixed in P-t-BS phase and the entanglements retards the
global motion of PIP At 70 the global motion of PIP in blend samples became close
to that of pure PIP suggesting that the PIP chains are not well entangled with P-t-BS
chains at high temperature It has been known that PIPP-t-BS blends exhibit
LCST-type phase behavior Changes of the global motion of PIP in blend samples with
temperature is consistent with this phase behavior
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
9
Normal stress development under large amplitude oscillatory
shear flow
Jung Gun Nam Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email guns2snuackr
Abstract The dynamic response of viscoelastic fluids under large amplitude oscillatory shear (LAOS) has been a subject of long history In recent years there seem to be progresses in this field More advanced instrumentation and new concepts are emerging In the LAOS flow the analysis has been mostly focused on shear stress possibly due to the lack of accurate measurement of normal stress However the normal stress may become larger than shear stress at high strain amplitudes and there are good reasons we need to understand the normal stress behavior As the instrumentation advances it becomes more feasible to get reliable data and this field will be more challenging The purpose of this paper is to develop a research platform to analyze and thereby to understand the normal stress behavior of complex fluids under LAOS flow We take the Giesekus model as a representative constitutive model and investigate diverse responses of the model We define new dynamic properties corresponding to normal stresses in a similar way to define dynamic moduli from shear stress and examine their behavior with various analyzing tools Experimental data are also compared with model predictions Though it is not yet possible to compare all the predictions due to instrumental limitation the prediction fits well with the experimental data and we hope this study provide a useful framework for further understanding of the nonlinear behavior of complex fluids under LAOS flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
10
Nonlinear behavior of complex fluids under large amplitude
oscillatory shear and squeezing flow
Juha Hwang
Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1580
Email jindols79hotmailcom
Abstract
The purpose of this research is to figure out viscoelastic behavior under large amplitude oscillatory shear (LAOS) and squeezing flow To analyze this behavior we have applied following nonlinear constitutive equations Upper convected Maxwell Giesekus FENE-P Marrucci Leonov Larson and Pom-pom model We analyzed the simulation results by modulus Fourier transform and stress decomposition which distinguishes elastic from viscous contribution to total stress The simulation results were compared with experimental data in other literatures Most constitutive equations predict LAOS behavior qualitatively in shear flow while only Larson model predicts LAOS behavior in squeezing flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
11
Studies on micro-convections induced in a polymer solution heated from above Yasuhiro YAMADA Shinichi SAKURAI
Polymer Science amp Engineering Kyoto Institute of Technology Kyoto Japan
We have reported micro-convections induced by the Soret effect in a polystyrene (PS)dioctylphthalate (DOP) solution under a temperature gradient (heated from below) The Soret effect stands for the fact that the concentration gradient is induced under the applied temperature gradient When temperature gradient is formed in a PSDOP solution PS is accumulated in the cooler side (upper side) by the Soret effect Then the concentrated PS solution undergoes sedimentation because the density of PS is higher than DOP Since this event can take place and result in a convective motion in a considerably thin layer of the solution (say 01 mm thickness) we refer to this as ldquomicro-convectionrdquo If the solvent density is larger than polymer a micro-convection can be induced even when such a solution is heated from above To examine this speculation we conducted experiments on a PStricresylphosphate (TCP) solution heated from above Note that the density of the solvent (TCP) is higher than that of PS Densities are 098 117 and 105 (gcm2) for DOP TCP and PS respectively
The samples used were PS (Mw=200k and MwMn=105) as a solute and TCP as a solvent The weight compositions are in the range of 01999 ~ 50950 The polymer solution was confined in a 05mm thickness layer Temperatures at the top and bottom plates Ttop and Tbot respectively were controlled independently by circulating temperature-regulated water being Ttop and Tbot at 35 and 65 respectively We observed such the polymer solution under a phase-contrast microscope As a result it was found that convection was generated in PSTCP solutions even when heated from above instead of being heated from below Fig 1 shows a typical result of a phase-contrast microscopic observation for the PSTCP sample (50950 composition) heated from below (a) and from above (b) In addition we analyzed dark meshes of convection to obtain brightness of the dark meshes based on which temporal changes in convection activity were examined In Fig2 were shown temporal changes in the brightness of the dark mesh for the PSTCP sample (50950 composition) Some oscillations were found and the brightness finally reached an asymptotic value It is interesting to note that a similar behavior was seen for the case of a PSDOP solution heated from bottom although the direction of the energy input is opposed
---------------------------------------------------------------------------------------------------------------- Corresponding author e-mail d2jyasmailgoonejp TEL 075-724-7864 FAX 075-724-7800
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
12
Development of a mixed-flow rheometer
Jae Hee Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email exodus55snuackr
Abstract This paper is concerned with the development of a mixed-flow rheometer for
determining the viscosity of a highly viscous filled viscoplastic fluid Recently there has been a renewal of interest in mixed-flow of viscoelastic fluid It is difficult to characterize the viscoelastic materials using conventional rheometer such as capillary rotational and compressional rheometers
In this study we develop a new rheometer for analysis of mixed-flow which is the combination of shear and compression mode This rheometer is designed for investigating the different microstructural rearrangement processes by the combination of two-deformation modes It is important to understand the combined-mode within an industrial quality control environment
In this presentation we will summarize the recent method for determination of the properties of viscoelastic systems under mixed-flow and provide a comprehensive mathematical theory for the interpretation of experimental data from the mixed-flow rheometer considering the influence of fluid inertia Also a series of experiments were carried out on a number of viscoelastic systems to confirm the theory
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
13
Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA Tadamine KIMU Hideshige SUZUKI Akihiro NISHIOKA
Tomonori KODA and Susumu IKEDA Department of Polymer Science and Engineering Yamagata University
Ikeda laboratry Yonezawa 992-8510 Japan E-mail dmx13313dipyzyamagata-uacjp
The purpose of this study is to clarify Ferroelectricity and Crystallization in
Poly(vinylidene fluoride)clay nanocomposites The ferroelectoricity in PVDFclay nanocomposites have been examined by measuring the D-E hysteresis loops The composites were also characterized by XRD DSC and TEM The nanocomposites were prepared by using melt compounding method This compounding was carried out by using the Twin Screw Extruder (TECHNOVEL Co Ltd model KZW-30 LD = 45) All samples for measurement were produced by hot press method at 200oC from dried pellet samples
As a result we found that the ferroelectricity can be observed in non-stretched PVDFclay nanocomposites films The PVDF crystal structure in its nanocomposites was similar to β form This results means that blending small amount of nano is one of the way to induce ferroelecticity of PVDF without stretching To clarify the mechanism of the induction ferroelecticity we have estimated lattice spacing of a clay surface by XRD The spacing between negatively charged oxygens on a clay surface is about 257Å which is almost the same spacing of monomer unit of PVDF in all trans chain conformation PVDF monomer on negatively charged clay surface has a permanent electrical dipole moment PVDF crystallites are epitaxially grown up on the clay surface in accordance with surface lattice structure
Acknowledgement We would like to thank for the cooperation of Prof KHAhn and all members of his
Laboratory in Seoul National University (SNU) Korea We would like to thank for providing us with TEM photos of our samples I would also like to thank Mr Namkung Mr Kim and Prof KH Ahn for their valuable comments suggestions support during my stay in Seoul National University (SNU)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
14
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Rheological characterization of hydrogel formed by the
blend of silk fibroin and hydroxypropylcellulose
Zuguang Gong Jinrong Yao Zhengzhong Shao
The Key Laboratory of Molecular Engineering of Polymer and Department of
Macromolecular Science Fudan University Shanghai 200433 China
Silk fibroin as the dominant protein in the raw Bombyx mori silk has a bright
prospect in biomedical application for its excellent morphological plasticity and
biocompatibility Hydroxypopylcellulose as one kind of water soluble cellulose
derivatives is a biocompatible polymer used for a wide range of applications in the food
pharmaceutical and cosmetic industries In our research the hydrogels formed by silk
fibroin and hydroxypropylcellulose blends were investigated using rheology We
focused on the concentration and component ratio dependence of the gelation time and
the elastic modulus of the hydrogel while the influence of shear (shear strain and
oscillatory frequency) on the dynamics of gelation process was investigated as silk
fibroin was highly shear-sensitive in aqueous solution (in nature the silkworms
conversion of the liquid dope to the solid fibre occurs through a strain-induced phase
separation) Also it was found that the addition of ions (K+ Ca+) has an effect on the
gelation behavior of such blend
Key words silk fibroin hydroxypropylcellulose hydrogel shear rheology
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
2
Relation between electric charges and beads formation on
Electro-spinning of Poly(vinyl alcohol)
Yosuke KADOMAE Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA
Department of Polymer Science and Engineering Yamagata University 4-3-16 Jonan Yonezawa 992-8510
TEL 0238-26-3058 FAX 0238-26-3411 Email kadomaeckpssyzyamagata-uacjp
Abstract We investigate formation of beads on electro-spinning by changing conductivity of poly
vinyl alcohol (PVA) aqueous solutions and spinning conditions such as applied voltage distance (L) between the tip of needle and the collector and humidity Electric conductivity of PVA aqueous solutions was controlled by changing amount of salt (NaCl)
From the results of experiments done by changing conductivity and spinning conditions we found that the beads formation is related to electric charges at the tip of sample Formation of beads is enhanced with increasing electric conductivity of PVA aqueous solutions Additionally in cases of changing the spinning conditions beads formation is suppressed at lower electric charges When the applied voltage changes to be same electric charge in respective distances between the tip of needle and the collector beads-less fibers are fabricated in all cases as shown in Fig1
Fig1 SEM images of electro-spun fibers at the same electric charge condition (a)75kV
and L=5cm (b) 9kV and L=10cm (c) 12kV and L=15cm (d) 14kV and L=20cm
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
3
Sensitivity of Low- and High-speed Spinning Process with Flow-Induced Crystallization Kinetics
Jang Ho Yun Dong Myeong Shin Joo Sung Lee Hyun Wook Jung
and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology
Center Korea University Seoul Korea
Recent issues of the spinning process are to investigate effect of crystallization (FIC) kinetics on the spinning dynamics Doufas et al (JNNFM 2000) and Kohler et al (J Macromol Sci-Phys 2005) predicted spinline deformation by employing their two-phase crystallinity models Regarding the FIC occurring on the spinline Joo et al (JNNFM 2002) simulated the nonisothermal spinline crystallization using two-dimensional model and Lee et al (JNNFM 2005) for the first time solved the transient responses of the low-speed spinning accompanied by FIC using a one-phase crystallinity model Shin et al (Korea-Australia Rheol J 2005 Rheol Acta 2006) also adopted this model to analyze the effect of the FIC on the spinning stability and neck-like deformation in high-speed spinning by linear stability method
However sensitivity of the spinning system has not been fully elucidated yet although this is an indispensable tool for the processability and product quality in industry In this study the sensitivity of both low- and high-speed spinning processes has been scrutinized by frequency response method measuring the amplitude ratio of output with respect to the infinitesimal sinusoidal disturbances in the linearized system (Jung et al Korea J Chem Eng 2004) In the low-speed spinning case there exists an optimal crystallinity region making the system the lowest sensitive to any disturbance In the high-speed case high inertia compensates for destabilizing effect by high crystallinity and makes the system generally less sensitive leading to the reduced resonance peaks by neck-like deformation Sensitivity results have closely been correlated with the previous ones by linear stability (Shin et al 2005 2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
4
Predicting permeability for fibrous porous media based on
micro-structure with direct simulation method
Jun Feng Wang Wook Ryol Hwang Shin Hyun Kang
School of Mechanical and Aerospace Engineering Gyeongsang National University South Korea
ABSTRACT
In this study a new finite element scheme is presented to investigate the permeability of fibrous porous media which is an important parameter in the resin transfer molding simulation A representative bi-periodic domain concept is introduced such that a single cell problem with a relatively small number of fiber filaments or fiber bundles may represent a large number of repeated structures of such a cell in the transversal planar flow through fiber arrays To use the regular rectangular mesh for the entire computation we employed a finite-element fictitious-domain method similar to the distributed Lagrangian multiplier method together with the rigid-ring description of the fiber The constraint for the bi-periodic domain is implemented by the mortar element method Examples of a single domain problem with one fiber 10 fibers and randomly distributed 100 fibers are investigated the normalized permeability shows approximately a uniform function of the fiber volume fraction which makes it possible to estimate the practical average permeability of fiber tows in several micro-meter scales The predicted results agree well with existing experimental data and numerical prediction in the literature In addition we present the permeability prediction for fiber bundles and investigate the effect of orientation on the permeability
The method we developed in this study is quite well suited for predicting the permeability of fibrous porous media and investigating the flow features in different micro-scale fiber architectures along with the inter-relationship between them Since the present scheme is based on the standard velocity-pressure formulation of the finite-element method it was also easily extended to the problem with non-Newtonian fluid medium In addition the present scheme was applied to three-dimensional problems with a tri-periodic unit cell In 3D cases the predicted permeability of porous media with regular packing fiber was compared with the results of other research
KEY WORDS Microstructure Finite element analysis Permeability Direct simulation Bi-periodic frame
Acknowledgement This work has been supported by the second stage BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
5
The effect of viscosity and flow rate on the droplet size and
formation pattern in T-shaped microchannel
Duwon Choi Sung Sik Lee Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
Tel 82-2-880-1579 E-mail tetra4646parancom
Abstract
It is important to characterize the size and formation pattern in order to manipulate
the small size (piconanoliter size) of droplets for chemical and biological applications Previously Garstecki et al investigated the size and formation pattern of micron-size droplets under low viscosity ratio condition In this study we conducted the experiments of micron-size droplets generation under wide range of viscosity ratio including above 1
This experiment was performed in a confined T-shaped microchannel made by soft lithography method Immiscible two liquids glycerol aqueous solution (dispersed flow) and corn oil (carrier flow) flow in the channel with rate ranging from 003ulmin to 5ulmin in each liquid flow We changed the viscosity ratio from 002 (DI water) to 28 (glycerol 90 in water) to understand the effect of viscosity on droplet size and formation pattern
We could obtain the maps of size and formation pattern as changing flow rate and viscosity ratio We expect that these maps help predict the size of droplets and their applications such as droplet based reaction (two droplets fusion) and generation of double emulsion
[1] P Garstecki M J Furestman H A Stone and G M White 2006 Labchip 5
437-446
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
6
Transient behaviors of immiscible polymer blends under varying flow
field
QUAN CHEN WEI YU CHIXING ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering Shanghai Jiao Tong University Shanghai 200240 P R China
One frequently used method on measuring thixotropy is to perform a loop test In
which changes in the structural level like the break-up and coalescence of the drops
cause measurable thixotropic behavior (Barnes HA (1997)) The flow field in our
experiment is the round trip (RT) test in which an additional opposite trip is added on
traditional thixotropic test The breakup and coalescence mechanics under such a flow
field is discussed here In addition a new model (Yu W and Zhou C (2006)) in which
breakup and coalescence is applied in our analysis
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
7
The effect of viscosity and elasticity on the DOD (Drop-On-Demand) inkjet drop formation
A Young Lee
Byoung Wook Jo Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1879
Email twinklesnuackr
Abstract Inkjet printing is familiar as a method of printing text and images onto substrates
such as paper In the last few years it has been explored as a way of printing electrical and optical devices with the use of specialty inks For a successful inkjet printing to be achieved in this area high resolution patternability is necessary Therefore it is essential to understand the mechanism of ink drop deformation and to reduce the satellite drop which can cause defect in printing
The breakup of viscoelastic jets has been studied by many researchers with a number of dilute and semidilute poly(ethylene oxide) solutions under the gravity Similarly the presence of small amounts of polymer in Newtonian solvents can cause a significant change of the drop-on-demand drop formation This study investigates the effect of viscosity and elasticity on the drop-on-demand drop formation through the use of Newtonian liquids and low viscosity elastic liquids The satellite drop produced by breakup of main drop is easily observed by Newtonian fluids Higher viscosity can suppress this satellite drop formation to some extent and the phenomena become significant when small amount of polymer is added To quantitatively characterize the behavior of drop deformation we compared jet retraction time and breakup time by employing jet stability graphs In jet stability graph the two critical jet speeds can suggest the relative jetting stability in terms of satellite drop generation Finally the effect of imposed pulse shape on drop formation is also studied
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
8
Dielectric Studies of Polymer Chain Dynamics in Polymer Blend
JunTakada HiroshiSasaki YoshiakiMatsushima AkiraKuriyama YumiMatsumiya
TadashiInoue HiroshiWatanabe
Toagosei CoLtd and Institute for Chemical ResearchKyoto University
We examined a relationship between polymer chain dynamics and phase separated
structure in polymer blends The samples used were blends of
polyisoprene(PIPMw=199times10 3 ) and poly-tert-butylstyrene(P-t-BS-HMw=700times10 3
P-t-BS-LMw=160times10 3 ) The blend ratio was PIPP-t-BS=82(wtwt) To discuss the
changes of polymer chain dynamics we investigated the dielectric loss ε rdquo of the blend
samples and pure PIP PIP has type-A dipoles that enable us to dielectrically observe
the global motion of PIP At 30 the global motion of PIP in the blend samples was
slower than that of pure PIP This result suggests that the PIP chains are entangled
with the P-t-BS chains ie mixed in P-t-BS phase and the entanglements retards the
global motion of PIP At 70 the global motion of PIP in blend samples became close
to that of pure PIP suggesting that the PIP chains are not well entangled with P-t-BS
chains at high temperature It has been known that PIPP-t-BS blends exhibit
LCST-type phase behavior Changes of the global motion of PIP in blend samples with
temperature is consistent with this phase behavior
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
9
Normal stress development under large amplitude oscillatory
shear flow
Jung Gun Nam Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email guns2snuackr
Abstract The dynamic response of viscoelastic fluids under large amplitude oscillatory shear (LAOS) has been a subject of long history In recent years there seem to be progresses in this field More advanced instrumentation and new concepts are emerging In the LAOS flow the analysis has been mostly focused on shear stress possibly due to the lack of accurate measurement of normal stress However the normal stress may become larger than shear stress at high strain amplitudes and there are good reasons we need to understand the normal stress behavior As the instrumentation advances it becomes more feasible to get reliable data and this field will be more challenging The purpose of this paper is to develop a research platform to analyze and thereby to understand the normal stress behavior of complex fluids under LAOS flow We take the Giesekus model as a representative constitutive model and investigate diverse responses of the model We define new dynamic properties corresponding to normal stresses in a similar way to define dynamic moduli from shear stress and examine their behavior with various analyzing tools Experimental data are also compared with model predictions Though it is not yet possible to compare all the predictions due to instrumental limitation the prediction fits well with the experimental data and we hope this study provide a useful framework for further understanding of the nonlinear behavior of complex fluids under LAOS flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
10
Nonlinear behavior of complex fluids under large amplitude
oscillatory shear and squeezing flow
Juha Hwang
Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1580
Email jindols79hotmailcom
Abstract
The purpose of this research is to figure out viscoelastic behavior under large amplitude oscillatory shear (LAOS) and squeezing flow To analyze this behavior we have applied following nonlinear constitutive equations Upper convected Maxwell Giesekus FENE-P Marrucci Leonov Larson and Pom-pom model We analyzed the simulation results by modulus Fourier transform and stress decomposition which distinguishes elastic from viscous contribution to total stress The simulation results were compared with experimental data in other literatures Most constitutive equations predict LAOS behavior qualitatively in shear flow while only Larson model predicts LAOS behavior in squeezing flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
11
Studies on micro-convections induced in a polymer solution heated from above Yasuhiro YAMADA Shinichi SAKURAI
Polymer Science amp Engineering Kyoto Institute of Technology Kyoto Japan
We have reported micro-convections induced by the Soret effect in a polystyrene (PS)dioctylphthalate (DOP) solution under a temperature gradient (heated from below) The Soret effect stands for the fact that the concentration gradient is induced under the applied temperature gradient When temperature gradient is formed in a PSDOP solution PS is accumulated in the cooler side (upper side) by the Soret effect Then the concentrated PS solution undergoes sedimentation because the density of PS is higher than DOP Since this event can take place and result in a convective motion in a considerably thin layer of the solution (say 01 mm thickness) we refer to this as ldquomicro-convectionrdquo If the solvent density is larger than polymer a micro-convection can be induced even when such a solution is heated from above To examine this speculation we conducted experiments on a PStricresylphosphate (TCP) solution heated from above Note that the density of the solvent (TCP) is higher than that of PS Densities are 098 117 and 105 (gcm2) for DOP TCP and PS respectively
The samples used were PS (Mw=200k and MwMn=105) as a solute and TCP as a solvent The weight compositions are in the range of 01999 ~ 50950 The polymer solution was confined in a 05mm thickness layer Temperatures at the top and bottom plates Ttop and Tbot respectively were controlled independently by circulating temperature-regulated water being Ttop and Tbot at 35 and 65 respectively We observed such the polymer solution under a phase-contrast microscope As a result it was found that convection was generated in PSTCP solutions even when heated from above instead of being heated from below Fig 1 shows a typical result of a phase-contrast microscopic observation for the PSTCP sample (50950 composition) heated from below (a) and from above (b) In addition we analyzed dark meshes of convection to obtain brightness of the dark meshes based on which temporal changes in convection activity were examined In Fig2 were shown temporal changes in the brightness of the dark mesh for the PSTCP sample (50950 composition) Some oscillations were found and the brightness finally reached an asymptotic value It is interesting to note that a similar behavior was seen for the case of a PSDOP solution heated from bottom although the direction of the energy input is opposed
---------------------------------------------------------------------------------------------------------------- Corresponding author e-mail d2jyasmailgoonejp TEL 075-724-7864 FAX 075-724-7800
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
12
Development of a mixed-flow rheometer
Jae Hee Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email exodus55snuackr
Abstract This paper is concerned with the development of a mixed-flow rheometer for
determining the viscosity of a highly viscous filled viscoplastic fluid Recently there has been a renewal of interest in mixed-flow of viscoelastic fluid It is difficult to characterize the viscoelastic materials using conventional rheometer such as capillary rotational and compressional rheometers
In this study we develop a new rheometer for analysis of mixed-flow which is the combination of shear and compression mode This rheometer is designed for investigating the different microstructural rearrangement processes by the combination of two-deformation modes It is important to understand the combined-mode within an industrial quality control environment
In this presentation we will summarize the recent method for determination of the properties of viscoelastic systems under mixed-flow and provide a comprehensive mathematical theory for the interpretation of experimental data from the mixed-flow rheometer considering the influence of fluid inertia Also a series of experiments were carried out on a number of viscoelastic systems to confirm the theory
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
13
Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA Tadamine KIMU Hideshige SUZUKI Akihiro NISHIOKA
Tomonori KODA and Susumu IKEDA Department of Polymer Science and Engineering Yamagata University
Ikeda laboratry Yonezawa 992-8510 Japan E-mail dmx13313dipyzyamagata-uacjp
The purpose of this study is to clarify Ferroelectricity and Crystallization in
Poly(vinylidene fluoride)clay nanocomposites The ferroelectoricity in PVDFclay nanocomposites have been examined by measuring the D-E hysteresis loops The composites were also characterized by XRD DSC and TEM The nanocomposites were prepared by using melt compounding method This compounding was carried out by using the Twin Screw Extruder (TECHNOVEL Co Ltd model KZW-30 LD = 45) All samples for measurement were produced by hot press method at 200oC from dried pellet samples
As a result we found that the ferroelectricity can be observed in non-stretched PVDFclay nanocomposites films The PVDF crystal structure in its nanocomposites was similar to β form This results means that blending small amount of nano is one of the way to induce ferroelecticity of PVDF without stretching To clarify the mechanism of the induction ferroelecticity we have estimated lattice spacing of a clay surface by XRD The spacing between negatively charged oxygens on a clay surface is about 257Å which is almost the same spacing of monomer unit of PVDF in all trans chain conformation PVDF monomer on negatively charged clay surface has a permanent electrical dipole moment PVDF crystallites are epitaxially grown up on the clay surface in accordance with surface lattice structure
Acknowledgement We would like to thank for the cooperation of Prof KHAhn and all members of his
Laboratory in Seoul National University (SNU) Korea We would like to thank for providing us with TEM photos of our samples I would also like to thank Mr Namkung Mr Kim and Prof KH Ahn for their valuable comments suggestions support during my stay in Seoul National University (SNU)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
14
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Relation between electric charges and beads formation on
Electro-spinning of Poly(vinyl alcohol)
Yosuke KADOMAE Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA
Department of Polymer Science and Engineering Yamagata University 4-3-16 Jonan Yonezawa 992-8510
TEL 0238-26-3058 FAX 0238-26-3411 Email kadomaeckpssyzyamagata-uacjp
Abstract We investigate formation of beads on electro-spinning by changing conductivity of poly
vinyl alcohol (PVA) aqueous solutions and spinning conditions such as applied voltage distance (L) between the tip of needle and the collector and humidity Electric conductivity of PVA aqueous solutions was controlled by changing amount of salt (NaCl)
From the results of experiments done by changing conductivity and spinning conditions we found that the beads formation is related to electric charges at the tip of sample Formation of beads is enhanced with increasing electric conductivity of PVA aqueous solutions Additionally in cases of changing the spinning conditions beads formation is suppressed at lower electric charges When the applied voltage changes to be same electric charge in respective distances between the tip of needle and the collector beads-less fibers are fabricated in all cases as shown in Fig1
Fig1 SEM images of electro-spun fibers at the same electric charge condition (a)75kV
and L=5cm (b) 9kV and L=10cm (c) 12kV and L=15cm (d) 14kV and L=20cm
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
3
Sensitivity of Low- and High-speed Spinning Process with Flow-Induced Crystallization Kinetics
Jang Ho Yun Dong Myeong Shin Joo Sung Lee Hyun Wook Jung
and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology
Center Korea University Seoul Korea
Recent issues of the spinning process are to investigate effect of crystallization (FIC) kinetics on the spinning dynamics Doufas et al (JNNFM 2000) and Kohler et al (J Macromol Sci-Phys 2005) predicted spinline deformation by employing their two-phase crystallinity models Regarding the FIC occurring on the spinline Joo et al (JNNFM 2002) simulated the nonisothermal spinline crystallization using two-dimensional model and Lee et al (JNNFM 2005) for the first time solved the transient responses of the low-speed spinning accompanied by FIC using a one-phase crystallinity model Shin et al (Korea-Australia Rheol J 2005 Rheol Acta 2006) also adopted this model to analyze the effect of the FIC on the spinning stability and neck-like deformation in high-speed spinning by linear stability method
However sensitivity of the spinning system has not been fully elucidated yet although this is an indispensable tool for the processability and product quality in industry In this study the sensitivity of both low- and high-speed spinning processes has been scrutinized by frequency response method measuring the amplitude ratio of output with respect to the infinitesimal sinusoidal disturbances in the linearized system (Jung et al Korea J Chem Eng 2004) In the low-speed spinning case there exists an optimal crystallinity region making the system the lowest sensitive to any disturbance In the high-speed case high inertia compensates for destabilizing effect by high crystallinity and makes the system generally less sensitive leading to the reduced resonance peaks by neck-like deformation Sensitivity results have closely been correlated with the previous ones by linear stability (Shin et al 2005 2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
4
Predicting permeability for fibrous porous media based on
micro-structure with direct simulation method
Jun Feng Wang Wook Ryol Hwang Shin Hyun Kang
School of Mechanical and Aerospace Engineering Gyeongsang National University South Korea
ABSTRACT
In this study a new finite element scheme is presented to investigate the permeability of fibrous porous media which is an important parameter in the resin transfer molding simulation A representative bi-periodic domain concept is introduced such that a single cell problem with a relatively small number of fiber filaments or fiber bundles may represent a large number of repeated structures of such a cell in the transversal planar flow through fiber arrays To use the regular rectangular mesh for the entire computation we employed a finite-element fictitious-domain method similar to the distributed Lagrangian multiplier method together with the rigid-ring description of the fiber The constraint for the bi-periodic domain is implemented by the mortar element method Examples of a single domain problem with one fiber 10 fibers and randomly distributed 100 fibers are investigated the normalized permeability shows approximately a uniform function of the fiber volume fraction which makes it possible to estimate the practical average permeability of fiber tows in several micro-meter scales The predicted results agree well with existing experimental data and numerical prediction in the literature In addition we present the permeability prediction for fiber bundles and investigate the effect of orientation on the permeability
The method we developed in this study is quite well suited for predicting the permeability of fibrous porous media and investigating the flow features in different micro-scale fiber architectures along with the inter-relationship between them Since the present scheme is based on the standard velocity-pressure formulation of the finite-element method it was also easily extended to the problem with non-Newtonian fluid medium In addition the present scheme was applied to three-dimensional problems with a tri-periodic unit cell In 3D cases the predicted permeability of porous media with regular packing fiber was compared with the results of other research
KEY WORDS Microstructure Finite element analysis Permeability Direct simulation Bi-periodic frame
Acknowledgement This work has been supported by the second stage BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
5
The effect of viscosity and flow rate on the droplet size and
formation pattern in T-shaped microchannel
Duwon Choi Sung Sik Lee Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
Tel 82-2-880-1579 E-mail tetra4646parancom
Abstract
It is important to characterize the size and formation pattern in order to manipulate
the small size (piconanoliter size) of droplets for chemical and biological applications Previously Garstecki et al investigated the size and formation pattern of micron-size droplets under low viscosity ratio condition In this study we conducted the experiments of micron-size droplets generation under wide range of viscosity ratio including above 1
This experiment was performed in a confined T-shaped microchannel made by soft lithography method Immiscible two liquids glycerol aqueous solution (dispersed flow) and corn oil (carrier flow) flow in the channel with rate ranging from 003ulmin to 5ulmin in each liquid flow We changed the viscosity ratio from 002 (DI water) to 28 (glycerol 90 in water) to understand the effect of viscosity on droplet size and formation pattern
We could obtain the maps of size and formation pattern as changing flow rate and viscosity ratio We expect that these maps help predict the size of droplets and their applications such as droplet based reaction (two droplets fusion) and generation of double emulsion
[1] P Garstecki M J Furestman H A Stone and G M White 2006 Labchip 5
437-446
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
6
Transient behaviors of immiscible polymer blends under varying flow
field
QUAN CHEN WEI YU CHIXING ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering Shanghai Jiao Tong University Shanghai 200240 P R China
One frequently used method on measuring thixotropy is to perform a loop test In
which changes in the structural level like the break-up and coalescence of the drops
cause measurable thixotropic behavior (Barnes HA (1997)) The flow field in our
experiment is the round trip (RT) test in which an additional opposite trip is added on
traditional thixotropic test The breakup and coalescence mechanics under such a flow
field is discussed here In addition a new model (Yu W and Zhou C (2006)) in which
breakup and coalescence is applied in our analysis
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
7
The effect of viscosity and elasticity on the DOD (Drop-On-Demand) inkjet drop formation
A Young Lee
Byoung Wook Jo Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1879
Email twinklesnuackr
Abstract Inkjet printing is familiar as a method of printing text and images onto substrates
such as paper In the last few years it has been explored as a way of printing electrical and optical devices with the use of specialty inks For a successful inkjet printing to be achieved in this area high resolution patternability is necessary Therefore it is essential to understand the mechanism of ink drop deformation and to reduce the satellite drop which can cause defect in printing
The breakup of viscoelastic jets has been studied by many researchers with a number of dilute and semidilute poly(ethylene oxide) solutions under the gravity Similarly the presence of small amounts of polymer in Newtonian solvents can cause a significant change of the drop-on-demand drop formation This study investigates the effect of viscosity and elasticity on the drop-on-demand drop formation through the use of Newtonian liquids and low viscosity elastic liquids The satellite drop produced by breakup of main drop is easily observed by Newtonian fluids Higher viscosity can suppress this satellite drop formation to some extent and the phenomena become significant when small amount of polymer is added To quantitatively characterize the behavior of drop deformation we compared jet retraction time and breakup time by employing jet stability graphs In jet stability graph the two critical jet speeds can suggest the relative jetting stability in terms of satellite drop generation Finally the effect of imposed pulse shape on drop formation is also studied
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
8
Dielectric Studies of Polymer Chain Dynamics in Polymer Blend
JunTakada HiroshiSasaki YoshiakiMatsushima AkiraKuriyama YumiMatsumiya
TadashiInoue HiroshiWatanabe
Toagosei CoLtd and Institute for Chemical ResearchKyoto University
We examined a relationship between polymer chain dynamics and phase separated
structure in polymer blends The samples used were blends of
polyisoprene(PIPMw=199times10 3 ) and poly-tert-butylstyrene(P-t-BS-HMw=700times10 3
P-t-BS-LMw=160times10 3 ) The blend ratio was PIPP-t-BS=82(wtwt) To discuss the
changes of polymer chain dynamics we investigated the dielectric loss ε rdquo of the blend
samples and pure PIP PIP has type-A dipoles that enable us to dielectrically observe
the global motion of PIP At 30 the global motion of PIP in the blend samples was
slower than that of pure PIP This result suggests that the PIP chains are entangled
with the P-t-BS chains ie mixed in P-t-BS phase and the entanglements retards the
global motion of PIP At 70 the global motion of PIP in blend samples became close
to that of pure PIP suggesting that the PIP chains are not well entangled with P-t-BS
chains at high temperature It has been known that PIPP-t-BS blends exhibit
LCST-type phase behavior Changes of the global motion of PIP in blend samples with
temperature is consistent with this phase behavior
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
9
Normal stress development under large amplitude oscillatory
shear flow
Jung Gun Nam Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email guns2snuackr
Abstract The dynamic response of viscoelastic fluids under large amplitude oscillatory shear (LAOS) has been a subject of long history In recent years there seem to be progresses in this field More advanced instrumentation and new concepts are emerging In the LAOS flow the analysis has been mostly focused on shear stress possibly due to the lack of accurate measurement of normal stress However the normal stress may become larger than shear stress at high strain amplitudes and there are good reasons we need to understand the normal stress behavior As the instrumentation advances it becomes more feasible to get reliable data and this field will be more challenging The purpose of this paper is to develop a research platform to analyze and thereby to understand the normal stress behavior of complex fluids under LAOS flow We take the Giesekus model as a representative constitutive model and investigate diverse responses of the model We define new dynamic properties corresponding to normal stresses in a similar way to define dynamic moduli from shear stress and examine their behavior with various analyzing tools Experimental data are also compared with model predictions Though it is not yet possible to compare all the predictions due to instrumental limitation the prediction fits well with the experimental data and we hope this study provide a useful framework for further understanding of the nonlinear behavior of complex fluids under LAOS flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
10
Nonlinear behavior of complex fluids under large amplitude
oscillatory shear and squeezing flow
Juha Hwang
Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1580
Email jindols79hotmailcom
Abstract
The purpose of this research is to figure out viscoelastic behavior under large amplitude oscillatory shear (LAOS) and squeezing flow To analyze this behavior we have applied following nonlinear constitutive equations Upper convected Maxwell Giesekus FENE-P Marrucci Leonov Larson and Pom-pom model We analyzed the simulation results by modulus Fourier transform and stress decomposition which distinguishes elastic from viscous contribution to total stress The simulation results were compared with experimental data in other literatures Most constitutive equations predict LAOS behavior qualitatively in shear flow while only Larson model predicts LAOS behavior in squeezing flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
11
Studies on micro-convections induced in a polymer solution heated from above Yasuhiro YAMADA Shinichi SAKURAI
Polymer Science amp Engineering Kyoto Institute of Technology Kyoto Japan
We have reported micro-convections induced by the Soret effect in a polystyrene (PS)dioctylphthalate (DOP) solution under a temperature gradient (heated from below) The Soret effect stands for the fact that the concentration gradient is induced under the applied temperature gradient When temperature gradient is formed in a PSDOP solution PS is accumulated in the cooler side (upper side) by the Soret effect Then the concentrated PS solution undergoes sedimentation because the density of PS is higher than DOP Since this event can take place and result in a convective motion in a considerably thin layer of the solution (say 01 mm thickness) we refer to this as ldquomicro-convectionrdquo If the solvent density is larger than polymer a micro-convection can be induced even when such a solution is heated from above To examine this speculation we conducted experiments on a PStricresylphosphate (TCP) solution heated from above Note that the density of the solvent (TCP) is higher than that of PS Densities are 098 117 and 105 (gcm2) for DOP TCP and PS respectively
The samples used were PS (Mw=200k and MwMn=105) as a solute and TCP as a solvent The weight compositions are in the range of 01999 ~ 50950 The polymer solution was confined in a 05mm thickness layer Temperatures at the top and bottom plates Ttop and Tbot respectively were controlled independently by circulating temperature-regulated water being Ttop and Tbot at 35 and 65 respectively We observed such the polymer solution under a phase-contrast microscope As a result it was found that convection was generated in PSTCP solutions even when heated from above instead of being heated from below Fig 1 shows a typical result of a phase-contrast microscopic observation for the PSTCP sample (50950 composition) heated from below (a) and from above (b) In addition we analyzed dark meshes of convection to obtain brightness of the dark meshes based on which temporal changes in convection activity were examined In Fig2 were shown temporal changes in the brightness of the dark mesh for the PSTCP sample (50950 composition) Some oscillations were found and the brightness finally reached an asymptotic value It is interesting to note that a similar behavior was seen for the case of a PSDOP solution heated from bottom although the direction of the energy input is opposed
---------------------------------------------------------------------------------------------------------------- Corresponding author e-mail d2jyasmailgoonejp TEL 075-724-7864 FAX 075-724-7800
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
12
Development of a mixed-flow rheometer
Jae Hee Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email exodus55snuackr
Abstract This paper is concerned with the development of a mixed-flow rheometer for
determining the viscosity of a highly viscous filled viscoplastic fluid Recently there has been a renewal of interest in mixed-flow of viscoelastic fluid It is difficult to characterize the viscoelastic materials using conventional rheometer such as capillary rotational and compressional rheometers
In this study we develop a new rheometer for analysis of mixed-flow which is the combination of shear and compression mode This rheometer is designed for investigating the different microstructural rearrangement processes by the combination of two-deformation modes It is important to understand the combined-mode within an industrial quality control environment
In this presentation we will summarize the recent method for determination of the properties of viscoelastic systems under mixed-flow and provide a comprehensive mathematical theory for the interpretation of experimental data from the mixed-flow rheometer considering the influence of fluid inertia Also a series of experiments were carried out on a number of viscoelastic systems to confirm the theory
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
13
Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA Tadamine KIMU Hideshige SUZUKI Akihiro NISHIOKA
Tomonori KODA and Susumu IKEDA Department of Polymer Science and Engineering Yamagata University
Ikeda laboratry Yonezawa 992-8510 Japan E-mail dmx13313dipyzyamagata-uacjp
The purpose of this study is to clarify Ferroelectricity and Crystallization in
Poly(vinylidene fluoride)clay nanocomposites The ferroelectoricity in PVDFclay nanocomposites have been examined by measuring the D-E hysteresis loops The composites were also characterized by XRD DSC and TEM The nanocomposites were prepared by using melt compounding method This compounding was carried out by using the Twin Screw Extruder (TECHNOVEL Co Ltd model KZW-30 LD = 45) All samples for measurement were produced by hot press method at 200oC from dried pellet samples
As a result we found that the ferroelectricity can be observed in non-stretched PVDFclay nanocomposites films The PVDF crystal structure in its nanocomposites was similar to β form This results means that blending small amount of nano is one of the way to induce ferroelecticity of PVDF without stretching To clarify the mechanism of the induction ferroelecticity we have estimated lattice spacing of a clay surface by XRD The spacing between negatively charged oxygens on a clay surface is about 257Å which is almost the same spacing of monomer unit of PVDF in all trans chain conformation PVDF monomer on negatively charged clay surface has a permanent electrical dipole moment PVDF crystallites are epitaxially grown up on the clay surface in accordance with surface lattice structure
Acknowledgement We would like to thank for the cooperation of Prof KHAhn and all members of his
Laboratory in Seoul National University (SNU) Korea We would like to thank for providing us with TEM photos of our samples I would also like to thank Mr Namkung Mr Kim and Prof KH Ahn for their valuable comments suggestions support during my stay in Seoul National University (SNU)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
14
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Sensitivity of Low- and High-speed Spinning Process with Flow-Induced Crystallization Kinetics
Jang Ho Yun Dong Myeong Shin Joo Sung Lee Hyun Wook Jung
and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology
Center Korea University Seoul Korea
Recent issues of the spinning process are to investigate effect of crystallization (FIC) kinetics on the spinning dynamics Doufas et al (JNNFM 2000) and Kohler et al (J Macromol Sci-Phys 2005) predicted spinline deformation by employing their two-phase crystallinity models Regarding the FIC occurring on the spinline Joo et al (JNNFM 2002) simulated the nonisothermal spinline crystallization using two-dimensional model and Lee et al (JNNFM 2005) for the first time solved the transient responses of the low-speed spinning accompanied by FIC using a one-phase crystallinity model Shin et al (Korea-Australia Rheol J 2005 Rheol Acta 2006) also adopted this model to analyze the effect of the FIC on the spinning stability and neck-like deformation in high-speed spinning by linear stability method
However sensitivity of the spinning system has not been fully elucidated yet although this is an indispensable tool for the processability and product quality in industry In this study the sensitivity of both low- and high-speed spinning processes has been scrutinized by frequency response method measuring the amplitude ratio of output with respect to the infinitesimal sinusoidal disturbances in the linearized system (Jung et al Korea J Chem Eng 2004) In the low-speed spinning case there exists an optimal crystallinity region making the system the lowest sensitive to any disturbance In the high-speed case high inertia compensates for destabilizing effect by high crystallinity and makes the system generally less sensitive leading to the reduced resonance peaks by neck-like deformation Sensitivity results have closely been correlated with the previous ones by linear stability (Shin et al 2005 2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
4
Predicting permeability for fibrous porous media based on
micro-structure with direct simulation method
Jun Feng Wang Wook Ryol Hwang Shin Hyun Kang
School of Mechanical and Aerospace Engineering Gyeongsang National University South Korea
ABSTRACT
In this study a new finite element scheme is presented to investigate the permeability of fibrous porous media which is an important parameter in the resin transfer molding simulation A representative bi-periodic domain concept is introduced such that a single cell problem with a relatively small number of fiber filaments or fiber bundles may represent a large number of repeated structures of such a cell in the transversal planar flow through fiber arrays To use the regular rectangular mesh for the entire computation we employed a finite-element fictitious-domain method similar to the distributed Lagrangian multiplier method together with the rigid-ring description of the fiber The constraint for the bi-periodic domain is implemented by the mortar element method Examples of a single domain problem with one fiber 10 fibers and randomly distributed 100 fibers are investigated the normalized permeability shows approximately a uniform function of the fiber volume fraction which makes it possible to estimate the practical average permeability of fiber tows in several micro-meter scales The predicted results agree well with existing experimental data and numerical prediction in the literature In addition we present the permeability prediction for fiber bundles and investigate the effect of orientation on the permeability
The method we developed in this study is quite well suited for predicting the permeability of fibrous porous media and investigating the flow features in different micro-scale fiber architectures along with the inter-relationship between them Since the present scheme is based on the standard velocity-pressure formulation of the finite-element method it was also easily extended to the problem with non-Newtonian fluid medium In addition the present scheme was applied to three-dimensional problems with a tri-periodic unit cell In 3D cases the predicted permeability of porous media with regular packing fiber was compared with the results of other research
KEY WORDS Microstructure Finite element analysis Permeability Direct simulation Bi-periodic frame
Acknowledgement This work has been supported by the second stage BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
5
The effect of viscosity and flow rate on the droplet size and
formation pattern in T-shaped microchannel
Duwon Choi Sung Sik Lee Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
Tel 82-2-880-1579 E-mail tetra4646parancom
Abstract
It is important to characterize the size and formation pattern in order to manipulate
the small size (piconanoliter size) of droplets for chemical and biological applications Previously Garstecki et al investigated the size and formation pattern of micron-size droplets under low viscosity ratio condition In this study we conducted the experiments of micron-size droplets generation under wide range of viscosity ratio including above 1
This experiment was performed in a confined T-shaped microchannel made by soft lithography method Immiscible two liquids glycerol aqueous solution (dispersed flow) and corn oil (carrier flow) flow in the channel with rate ranging from 003ulmin to 5ulmin in each liquid flow We changed the viscosity ratio from 002 (DI water) to 28 (glycerol 90 in water) to understand the effect of viscosity on droplet size and formation pattern
We could obtain the maps of size and formation pattern as changing flow rate and viscosity ratio We expect that these maps help predict the size of droplets and their applications such as droplet based reaction (two droplets fusion) and generation of double emulsion
[1] P Garstecki M J Furestman H A Stone and G M White 2006 Labchip 5
437-446
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
6
Transient behaviors of immiscible polymer blends under varying flow
field
QUAN CHEN WEI YU CHIXING ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering Shanghai Jiao Tong University Shanghai 200240 P R China
One frequently used method on measuring thixotropy is to perform a loop test In
which changes in the structural level like the break-up and coalescence of the drops
cause measurable thixotropic behavior (Barnes HA (1997)) The flow field in our
experiment is the round trip (RT) test in which an additional opposite trip is added on
traditional thixotropic test The breakup and coalescence mechanics under such a flow
field is discussed here In addition a new model (Yu W and Zhou C (2006)) in which
breakup and coalescence is applied in our analysis
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
7
The effect of viscosity and elasticity on the DOD (Drop-On-Demand) inkjet drop formation
A Young Lee
Byoung Wook Jo Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1879
Email twinklesnuackr
Abstract Inkjet printing is familiar as a method of printing text and images onto substrates
such as paper In the last few years it has been explored as a way of printing electrical and optical devices with the use of specialty inks For a successful inkjet printing to be achieved in this area high resolution patternability is necessary Therefore it is essential to understand the mechanism of ink drop deformation and to reduce the satellite drop which can cause defect in printing
The breakup of viscoelastic jets has been studied by many researchers with a number of dilute and semidilute poly(ethylene oxide) solutions under the gravity Similarly the presence of small amounts of polymer in Newtonian solvents can cause a significant change of the drop-on-demand drop formation This study investigates the effect of viscosity and elasticity on the drop-on-demand drop formation through the use of Newtonian liquids and low viscosity elastic liquids The satellite drop produced by breakup of main drop is easily observed by Newtonian fluids Higher viscosity can suppress this satellite drop formation to some extent and the phenomena become significant when small amount of polymer is added To quantitatively characterize the behavior of drop deformation we compared jet retraction time and breakup time by employing jet stability graphs In jet stability graph the two critical jet speeds can suggest the relative jetting stability in terms of satellite drop generation Finally the effect of imposed pulse shape on drop formation is also studied
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
8
Dielectric Studies of Polymer Chain Dynamics in Polymer Blend
JunTakada HiroshiSasaki YoshiakiMatsushima AkiraKuriyama YumiMatsumiya
TadashiInoue HiroshiWatanabe
Toagosei CoLtd and Institute for Chemical ResearchKyoto University
We examined a relationship between polymer chain dynamics and phase separated
structure in polymer blends The samples used were blends of
polyisoprene(PIPMw=199times10 3 ) and poly-tert-butylstyrene(P-t-BS-HMw=700times10 3
P-t-BS-LMw=160times10 3 ) The blend ratio was PIPP-t-BS=82(wtwt) To discuss the
changes of polymer chain dynamics we investigated the dielectric loss ε rdquo of the blend
samples and pure PIP PIP has type-A dipoles that enable us to dielectrically observe
the global motion of PIP At 30 the global motion of PIP in the blend samples was
slower than that of pure PIP This result suggests that the PIP chains are entangled
with the P-t-BS chains ie mixed in P-t-BS phase and the entanglements retards the
global motion of PIP At 70 the global motion of PIP in blend samples became close
to that of pure PIP suggesting that the PIP chains are not well entangled with P-t-BS
chains at high temperature It has been known that PIPP-t-BS blends exhibit
LCST-type phase behavior Changes of the global motion of PIP in blend samples with
temperature is consistent with this phase behavior
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
9
Normal stress development under large amplitude oscillatory
shear flow
Jung Gun Nam Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email guns2snuackr
Abstract The dynamic response of viscoelastic fluids under large amplitude oscillatory shear (LAOS) has been a subject of long history In recent years there seem to be progresses in this field More advanced instrumentation and new concepts are emerging In the LAOS flow the analysis has been mostly focused on shear stress possibly due to the lack of accurate measurement of normal stress However the normal stress may become larger than shear stress at high strain amplitudes and there are good reasons we need to understand the normal stress behavior As the instrumentation advances it becomes more feasible to get reliable data and this field will be more challenging The purpose of this paper is to develop a research platform to analyze and thereby to understand the normal stress behavior of complex fluids under LAOS flow We take the Giesekus model as a representative constitutive model and investigate diverse responses of the model We define new dynamic properties corresponding to normal stresses in a similar way to define dynamic moduli from shear stress and examine their behavior with various analyzing tools Experimental data are also compared with model predictions Though it is not yet possible to compare all the predictions due to instrumental limitation the prediction fits well with the experimental data and we hope this study provide a useful framework for further understanding of the nonlinear behavior of complex fluids under LAOS flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
10
Nonlinear behavior of complex fluids under large amplitude
oscillatory shear and squeezing flow
Juha Hwang
Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1580
Email jindols79hotmailcom
Abstract
The purpose of this research is to figure out viscoelastic behavior under large amplitude oscillatory shear (LAOS) and squeezing flow To analyze this behavior we have applied following nonlinear constitutive equations Upper convected Maxwell Giesekus FENE-P Marrucci Leonov Larson and Pom-pom model We analyzed the simulation results by modulus Fourier transform and stress decomposition which distinguishes elastic from viscous contribution to total stress The simulation results were compared with experimental data in other literatures Most constitutive equations predict LAOS behavior qualitatively in shear flow while only Larson model predicts LAOS behavior in squeezing flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
11
Studies on micro-convections induced in a polymer solution heated from above Yasuhiro YAMADA Shinichi SAKURAI
Polymer Science amp Engineering Kyoto Institute of Technology Kyoto Japan
We have reported micro-convections induced by the Soret effect in a polystyrene (PS)dioctylphthalate (DOP) solution under a temperature gradient (heated from below) The Soret effect stands for the fact that the concentration gradient is induced under the applied temperature gradient When temperature gradient is formed in a PSDOP solution PS is accumulated in the cooler side (upper side) by the Soret effect Then the concentrated PS solution undergoes sedimentation because the density of PS is higher than DOP Since this event can take place and result in a convective motion in a considerably thin layer of the solution (say 01 mm thickness) we refer to this as ldquomicro-convectionrdquo If the solvent density is larger than polymer a micro-convection can be induced even when such a solution is heated from above To examine this speculation we conducted experiments on a PStricresylphosphate (TCP) solution heated from above Note that the density of the solvent (TCP) is higher than that of PS Densities are 098 117 and 105 (gcm2) for DOP TCP and PS respectively
The samples used were PS (Mw=200k and MwMn=105) as a solute and TCP as a solvent The weight compositions are in the range of 01999 ~ 50950 The polymer solution was confined in a 05mm thickness layer Temperatures at the top and bottom plates Ttop and Tbot respectively were controlled independently by circulating temperature-regulated water being Ttop and Tbot at 35 and 65 respectively We observed such the polymer solution under a phase-contrast microscope As a result it was found that convection was generated in PSTCP solutions even when heated from above instead of being heated from below Fig 1 shows a typical result of a phase-contrast microscopic observation for the PSTCP sample (50950 composition) heated from below (a) and from above (b) In addition we analyzed dark meshes of convection to obtain brightness of the dark meshes based on which temporal changes in convection activity were examined In Fig2 were shown temporal changes in the brightness of the dark mesh for the PSTCP sample (50950 composition) Some oscillations were found and the brightness finally reached an asymptotic value It is interesting to note that a similar behavior was seen for the case of a PSDOP solution heated from bottom although the direction of the energy input is opposed
---------------------------------------------------------------------------------------------------------------- Corresponding author e-mail d2jyasmailgoonejp TEL 075-724-7864 FAX 075-724-7800
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
12
Development of a mixed-flow rheometer
Jae Hee Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email exodus55snuackr
Abstract This paper is concerned with the development of a mixed-flow rheometer for
determining the viscosity of a highly viscous filled viscoplastic fluid Recently there has been a renewal of interest in mixed-flow of viscoelastic fluid It is difficult to characterize the viscoelastic materials using conventional rheometer such as capillary rotational and compressional rheometers
In this study we develop a new rheometer for analysis of mixed-flow which is the combination of shear and compression mode This rheometer is designed for investigating the different microstructural rearrangement processes by the combination of two-deformation modes It is important to understand the combined-mode within an industrial quality control environment
In this presentation we will summarize the recent method for determination of the properties of viscoelastic systems under mixed-flow and provide a comprehensive mathematical theory for the interpretation of experimental data from the mixed-flow rheometer considering the influence of fluid inertia Also a series of experiments were carried out on a number of viscoelastic systems to confirm the theory
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
13
Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA Tadamine KIMU Hideshige SUZUKI Akihiro NISHIOKA
Tomonori KODA and Susumu IKEDA Department of Polymer Science and Engineering Yamagata University
Ikeda laboratry Yonezawa 992-8510 Japan E-mail dmx13313dipyzyamagata-uacjp
The purpose of this study is to clarify Ferroelectricity and Crystallization in
Poly(vinylidene fluoride)clay nanocomposites The ferroelectoricity in PVDFclay nanocomposites have been examined by measuring the D-E hysteresis loops The composites were also characterized by XRD DSC and TEM The nanocomposites were prepared by using melt compounding method This compounding was carried out by using the Twin Screw Extruder (TECHNOVEL Co Ltd model KZW-30 LD = 45) All samples for measurement were produced by hot press method at 200oC from dried pellet samples
As a result we found that the ferroelectricity can be observed in non-stretched PVDFclay nanocomposites films The PVDF crystal structure in its nanocomposites was similar to β form This results means that blending small amount of nano is one of the way to induce ferroelecticity of PVDF without stretching To clarify the mechanism of the induction ferroelecticity we have estimated lattice spacing of a clay surface by XRD The spacing between negatively charged oxygens on a clay surface is about 257Å which is almost the same spacing of monomer unit of PVDF in all trans chain conformation PVDF monomer on negatively charged clay surface has a permanent electrical dipole moment PVDF crystallites are epitaxially grown up on the clay surface in accordance with surface lattice structure
Acknowledgement We would like to thank for the cooperation of Prof KHAhn and all members of his
Laboratory in Seoul National University (SNU) Korea We would like to thank for providing us with TEM photos of our samples I would also like to thank Mr Namkung Mr Kim and Prof KH Ahn for their valuable comments suggestions support during my stay in Seoul National University (SNU)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
14
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Predicting permeability for fibrous porous media based on
micro-structure with direct simulation method
Jun Feng Wang Wook Ryol Hwang Shin Hyun Kang
School of Mechanical and Aerospace Engineering Gyeongsang National University South Korea
ABSTRACT
In this study a new finite element scheme is presented to investigate the permeability of fibrous porous media which is an important parameter in the resin transfer molding simulation A representative bi-periodic domain concept is introduced such that a single cell problem with a relatively small number of fiber filaments or fiber bundles may represent a large number of repeated structures of such a cell in the transversal planar flow through fiber arrays To use the regular rectangular mesh for the entire computation we employed a finite-element fictitious-domain method similar to the distributed Lagrangian multiplier method together with the rigid-ring description of the fiber The constraint for the bi-periodic domain is implemented by the mortar element method Examples of a single domain problem with one fiber 10 fibers and randomly distributed 100 fibers are investigated the normalized permeability shows approximately a uniform function of the fiber volume fraction which makes it possible to estimate the practical average permeability of fiber tows in several micro-meter scales The predicted results agree well with existing experimental data and numerical prediction in the literature In addition we present the permeability prediction for fiber bundles and investigate the effect of orientation on the permeability
The method we developed in this study is quite well suited for predicting the permeability of fibrous porous media and investigating the flow features in different micro-scale fiber architectures along with the inter-relationship between them Since the present scheme is based on the standard velocity-pressure formulation of the finite-element method it was also easily extended to the problem with non-Newtonian fluid medium In addition the present scheme was applied to three-dimensional problems with a tri-periodic unit cell In 3D cases the predicted permeability of porous media with regular packing fiber was compared with the results of other research
KEY WORDS Microstructure Finite element analysis Permeability Direct simulation Bi-periodic frame
Acknowledgement This work has been supported by the second stage BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
5
The effect of viscosity and flow rate on the droplet size and
formation pattern in T-shaped microchannel
Duwon Choi Sung Sik Lee Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
Tel 82-2-880-1579 E-mail tetra4646parancom
Abstract
It is important to characterize the size and formation pattern in order to manipulate
the small size (piconanoliter size) of droplets for chemical and biological applications Previously Garstecki et al investigated the size and formation pattern of micron-size droplets under low viscosity ratio condition In this study we conducted the experiments of micron-size droplets generation under wide range of viscosity ratio including above 1
This experiment was performed in a confined T-shaped microchannel made by soft lithography method Immiscible two liquids glycerol aqueous solution (dispersed flow) and corn oil (carrier flow) flow in the channel with rate ranging from 003ulmin to 5ulmin in each liquid flow We changed the viscosity ratio from 002 (DI water) to 28 (glycerol 90 in water) to understand the effect of viscosity on droplet size and formation pattern
We could obtain the maps of size and formation pattern as changing flow rate and viscosity ratio We expect that these maps help predict the size of droplets and their applications such as droplet based reaction (two droplets fusion) and generation of double emulsion
[1] P Garstecki M J Furestman H A Stone and G M White 2006 Labchip 5
437-446
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
6
Transient behaviors of immiscible polymer blends under varying flow
field
QUAN CHEN WEI YU CHIXING ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering Shanghai Jiao Tong University Shanghai 200240 P R China
One frequently used method on measuring thixotropy is to perform a loop test In
which changes in the structural level like the break-up and coalescence of the drops
cause measurable thixotropic behavior (Barnes HA (1997)) The flow field in our
experiment is the round trip (RT) test in which an additional opposite trip is added on
traditional thixotropic test The breakup and coalescence mechanics under such a flow
field is discussed here In addition a new model (Yu W and Zhou C (2006)) in which
breakup and coalescence is applied in our analysis
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
7
The effect of viscosity and elasticity on the DOD (Drop-On-Demand) inkjet drop formation
A Young Lee
Byoung Wook Jo Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1879
Email twinklesnuackr
Abstract Inkjet printing is familiar as a method of printing text and images onto substrates
such as paper In the last few years it has been explored as a way of printing electrical and optical devices with the use of specialty inks For a successful inkjet printing to be achieved in this area high resolution patternability is necessary Therefore it is essential to understand the mechanism of ink drop deformation and to reduce the satellite drop which can cause defect in printing
The breakup of viscoelastic jets has been studied by many researchers with a number of dilute and semidilute poly(ethylene oxide) solutions under the gravity Similarly the presence of small amounts of polymer in Newtonian solvents can cause a significant change of the drop-on-demand drop formation This study investigates the effect of viscosity and elasticity on the drop-on-demand drop formation through the use of Newtonian liquids and low viscosity elastic liquids The satellite drop produced by breakup of main drop is easily observed by Newtonian fluids Higher viscosity can suppress this satellite drop formation to some extent and the phenomena become significant when small amount of polymer is added To quantitatively characterize the behavior of drop deformation we compared jet retraction time and breakup time by employing jet stability graphs In jet stability graph the two critical jet speeds can suggest the relative jetting stability in terms of satellite drop generation Finally the effect of imposed pulse shape on drop formation is also studied
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
8
Dielectric Studies of Polymer Chain Dynamics in Polymer Blend
JunTakada HiroshiSasaki YoshiakiMatsushima AkiraKuriyama YumiMatsumiya
TadashiInoue HiroshiWatanabe
Toagosei CoLtd and Institute for Chemical ResearchKyoto University
We examined a relationship between polymer chain dynamics and phase separated
structure in polymer blends The samples used were blends of
polyisoprene(PIPMw=199times10 3 ) and poly-tert-butylstyrene(P-t-BS-HMw=700times10 3
P-t-BS-LMw=160times10 3 ) The blend ratio was PIPP-t-BS=82(wtwt) To discuss the
changes of polymer chain dynamics we investigated the dielectric loss ε rdquo of the blend
samples and pure PIP PIP has type-A dipoles that enable us to dielectrically observe
the global motion of PIP At 30 the global motion of PIP in the blend samples was
slower than that of pure PIP This result suggests that the PIP chains are entangled
with the P-t-BS chains ie mixed in P-t-BS phase and the entanglements retards the
global motion of PIP At 70 the global motion of PIP in blend samples became close
to that of pure PIP suggesting that the PIP chains are not well entangled with P-t-BS
chains at high temperature It has been known that PIPP-t-BS blends exhibit
LCST-type phase behavior Changes of the global motion of PIP in blend samples with
temperature is consistent with this phase behavior
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
9
Normal stress development under large amplitude oscillatory
shear flow
Jung Gun Nam Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email guns2snuackr
Abstract The dynamic response of viscoelastic fluids under large amplitude oscillatory shear (LAOS) has been a subject of long history In recent years there seem to be progresses in this field More advanced instrumentation and new concepts are emerging In the LAOS flow the analysis has been mostly focused on shear stress possibly due to the lack of accurate measurement of normal stress However the normal stress may become larger than shear stress at high strain amplitudes and there are good reasons we need to understand the normal stress behavior As the instrumentation advances it becomes more feasible to get reliable data and this field will be more challenging The purpose of this paper is to develop a research platform to analyze and thereby to understand the normal stress behavior of complex fluids under LAOS flow We take the Giesekus model as a representative constitutive model and investigate diverse responses of the model We define new dynamic properties corresponding to normal stresses in a similar way to define dynamic moduli from shear stress and examine their behavior with various analyzing tools Experimental data are also compared with model predictions Though it is not yet possible to compare all the predictions due to instrumental limitation the prediction fits well with the experimental data and we hope this study provide a useful framework for further understanding of the nonlinear behavior of complex fluids under LAOS flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
10
Nonlinear behavior of complex fluids under large amplitude
oscillatory shear and squeezing flow
Juha Hwang
Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1580
Email jindols79hotmailcom
Abstract
The purpose of this research is to figure out viscoelastic behavior under large amplitude oscillatory shear (LAOS) and squeezing flow To analyze this behavior we have applied following nonlinear constitutive equations Upper convected Maxwell Giesekus FENE-P Marrucci Leonov Larson and Pom-pom model We analyzed the simulation results by modulus Fourier transform and stress decomposition which distinguishes elastic from viscous contribution to total stress The simulation results were compared with experimental data in other literatures Most constitutive equations predict LAOS behavior qualitatively in shear flow while only Larson model predicts LAOS behavior in squeezing flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
11
Studies on micro-convections induced in a polymer solution heated from above Yasuhiro YAMADA Shinichi SAKURAI
Polymer Science amp Engineering Kyoto Institute of Technology Kyoto Japan
We have reported micro-convections induced by the Soret effect in a polystyrene (PS)dioctylphthalate (DOP) solution under a temperature gradient (heated from below) The Soret effect stands for the fact that the concentration gradient is induced under the applied temperature gradient When temperature gradient is formed in a PSDOP solution PS is accumulated in the cooler side (upper side) by the Soret effect Then the concentrated PS solution undergoes sedimentation because the density of PS is higher than DOP Since this event can take place and result in a convective motion in a considerably thin layer of the solution (say 01 mm thickness) we refer to this as ldquomicro-convectionrdquo If the solvent density is larger than polymer a micro-convection can be induced even when such a solution is heated from above To examine this speculation we conducted experiments on a PStricresylphosphate (TCP) solution heated from above Note that the density of the solvent (TCP) is higher than that of PS Densities are 098 117 and 105 (gcm2) for DOP TCP and PS respectively
The samples used were PS (Mw=200k and MwMn=105) as a solute and TCP as a solvent The weight compositions are in the range of 01999 ~ 50950 The polymer solution was confined in a 05mm thickness layer Temperatures at the top and bottom plates Ttop and Tbot respectively were controlled independently by circulating temperature-regulated water being Ttop and Tbot at 35 and 65 respectively We observed such the polymer solution under a phase-contrast microscope As a result it was found that convection was generated in PSTCP solutions even when heated from above instead of being heated from below Fig 1 shows a typical result of a phase-contrast microscopic observation for the PSTCP sample (50950 composition) heated from below (a) and from above (b) In addition we analyzed dark meshes of convection to obtain brightness of the dark meshes based on which temporal changes in convection activity were examined In Fig2 were shown temporal changes in the brightness of the dark mesh for the PSTCP sample (50950 composition) Some oscillations were found and the brightness finally reached an asymptotic value It is interesting to note that a similar behavior was seen for the case of a PSDOP solution heated from bottom although the direction of the energy input is opposed
---------------------------------------------------------------------------------------------------------------- Corresponding author e-mail d2jyasmailgoonejp TEL 075-724-7864 FAX 075-724-7800
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
12
Development of a mixed-flow rheometer
Jae Hee Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email exodus55snuackr
Abstract This paper is concerned with the development of a mixed-flow rheometer for
determining the viscosity of a highly viscous filled viscoplastic fluid Recently there has been a renewal of interest in mixed-flow of viscoelastic fluid It is difficult to characterize the viscoelastic materials using conventional rheometer such as capillary rotational and compressional rheometers
In this study we develop a new rheometer for analysis of mixed-flow which is the combination of shear and compression mode This rheometer is designed for investigating the different microstructural rearrangement processes by the combination of two-deformation modes It is important to understand the combined-mode within an industrial quality control environment
In this presentation we will summarize the recent method for determination of the properties of viscoelastic systems under mixed-flow and provide a comprehensive mathematical theory for the interpretation of experimental data from the mixed-flow rheometer considering the influence of fluid inertia Also a series of experiments were carried out on a number of viscoelastic systems to confirm the theory
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
13
Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA Tadamine KIMU Hideshige SUZUKI Akihiro NISHIOKA
Tomonori KODA and Susumu IKEDA Department of Polymer Science and Engineering Yamagata University
Ikeda laboratry Yonezawa 992-8510 Japan E-mail dmx13313dipyzyamagata-uacjp
The purpose of this study is to clarify Ferroelectricity and Crystallization in
Poly(vinylidene fluoride)clay nanocomposites The ferroelectoricity in PVDFclay nanocomposites have been examined by measuring the D-E hysteresis loops The composites were also characterized by XRD DSC and TEM The nanocomposites were prepared by using melt compounding method This compounding was carried out by using the Twin Screw Extruder (TECHNOVEL Co Ltd model KZW-30 LD = 45) All samples for measurement were produced by hot press method at 200oC from dried pellet samples
As a result we found that the ferroelectricity can be observed in non-stretched PVDFclay nanocomposites films The PVDF crystal structure in its nanocomposites was similar to β form This results means that blending small amount of nano is one of the way to induce ferroelecticity of PVDF without stretching To clarify the mechanism of the induction ferroelecticity we have estimated lattice spacing of a clay surface by XRD The spacing between negatively charged oxygens on a clay surface is about 257Å which is almost the same spacing of monomer unit of PVDF in all trans chain conformation PVDF monomer on negatively charged clay surface has a permanent electrical dipole moment PVDF crystallites are epitaxially grown up on the clay surface in accordance with surface lattice structure
Acknowledgement We would like to thank for the cooperation of Prof KHAhn and all members of his
Laboratory in Seoul National University (SNU) Korea We would like to thank for providing us with TEM photos of our samples I would also like to thank Mr Namkung Mr Kim and Prof KH Ahn for their valuable comments suggestions support during my stay in Seoul National University (SNU)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
14
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
The effect of viscosity and flow rate on the droplet size and
formation pattern in T-shaped microchannel
Duwon Choi Sung Sik Lee Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
Tel 82-2-880-1579 E-mail tetra4646parancom
Abstract
It is important to characterize the size and formation pattern in order to manipulate
the small size (piconanoliter size) of droplets for chemical and biological applications Previously Garstecki et al investigated the size and formation pattern of micron-size droplets under low viscosity ratio condition In this study we conducted the experiments of micron-size droplets generation under wide range of viscosity ratio including above 1
This experiment was performed in a confined T-shaped microchannel made by soft lithography method Immiscible two liquids glycerol aqueous solution (dispersed flow) and corn oil (carrier flow) flow in the channel with rate ranging from 003ulmin to 5ulmin in each liquid flow We changed the viscosity ratio from 002 (DI water) to 28 (glycerol 90 in water) to understand the effect of viscosity on droplet size and formation pattern
We could obtain the maps of size and formation pattern as changing flow rate and viscosity ratio We expect that these maps help predict the size of droplets and their applications such as droplet based reaction (two droplets fusion) and generation of double emulsion
[1] P Garstecki M J Furestman H A Stone and G M White 2006 Labchip 5
437-446
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
6
Transient behaviors of immiscible polymer blends under varying flow
field
QUAN CHEN WEI YU CHIXING ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering Shanghai Jiao Tong University Shanghai 200240 P R China
One frequently used method on measuring thixotropy is to perform a loop test In
which changes in the structural level like the break-up and coalescence of the drops
cause measurable thixotropic behavior (Barnes HA (1997)) The flow field in our
experiment is the round trip (RT) test in which an additional opposite trip is added on
traditional thixotropic test The breakup and coalescence mechanics under such a flow
field is discussed here In addition a new model (Yu W and Zhou C (2006)) in which
breakup and coalescence is applied in our analysis
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
7
The effect of viscosity and elasticity on the DOD (Drop-On-Demand) inkjet drop formation
A Young Lee
Byoung Wook Jo Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1879
Email twinklesnuackr
Abstract Inkjet printing is familiar as a method of printing text and images onto substrates
such as paper In the last few years it has been explored as a way of printing electrical and optical devices with the use of specialty inks For a successful inkjet printing to be achieved in this area high resolution patternability is necessary Therefore it is essential to understand the mechanism of ink drop deformation and to reduce the satellite drop which can cause defect in printing
The breakup of viscoelastic jets has been studied by many researchers with a number of dilute and semidilute poly(ethylene oxide) solutions under the gravity Similarly the presence of small amounts of polymer in Newtonian solvents can cause a significant change of the drop-on-demand drop formation This study investigates the effect of viscosity and elasticity on the drop-on-demand drop formation through the use of Newtonian liquids and low viscosity elastic liquids The satellite drop produced by breakup of main drop is easily observed by Newtonian fluids Higher viscosity can suppress this satellite drop formation to some extent and the phenomena become significant when small amount of polymer is added To quantitatively characterize the behavior of drop deformation we compared jet retraction time and breakup time by employing jet stability graphs In jet stability graph the two critical jet speeds can suggest the relative jetting stability in terms of satellite drop generation Finally the effect of imposed pulse shape on drop formation is also studied
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
8
Dielectric Studies of Polymer Chain Dynamics in Polymer Blend
JunTakada HiroshiSasaki YoshiakiMatsushima AkiraKuriyama YumiMatsumiya
TadashiInoue HiroshiWatanabe
Toagosei CoLtd and Institute for Chemical ResearchKyoto University
We examined a relationship between polymer chain dynamics and phase separated
structure in polymer blends The samples used were blends of
polyisoprene(PIPMw=199times10 3 ) and poly-tert-butylstyrene(P-t-BS-HMw=700times10 3
P-t-BS-LMw=160times10 3 ) The blend ratio was PIPP-t-BS=82(wtwt) To discuss the
changes of polymer chain dynamics we investigated the dielectric loss ε rdquo of the blend
samples and pure PIP PIP has type-A dipoles that enable us to dielectrically observe
the global motion of PIP At 30 the global motion of PIP in the blend samples was
slower than that of pure PIP This result suggests that the PIP chains are entangled
with the P-t-BS chains ie mixed in P-t-BS phase and the entanglements retards the
global motion of PIP At 70 the global motion of PIP in blend samples became close
to that of pure PIP suggesting that the PIP chains are not well entangled with P-t-BS
chains at high temperature It has been known that PIPP-t-BS blends exhibit
LCST-type phase behavior Changes of the global motion of PIP in blend samples with
temperature is consistent with this phase behavior
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
9
Normal stress development under large amplitude oscillatory
shear flow
Jung Gun Nam Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email guns2snuackr
Abstract The dynamic response of viscoelastic fluids under large amplitude oscillatory shear (LAOS) has been a subject of long history In recent years there seem to be progresses in this field More advanced instrumentation and new concepts are emerging In the LAOS flow the analysis has been mostly focused on shear stress possibly due to the lack of accurate measurement of normal stress However the normal stress may become larger than shear stress at high strain amplitudes and there are good reasons we need to understand the normal stress behavior As the instrumentation advances it becomes more feasible to get reliable data and this field will be more challenging The purpose of this paper is to develop a research platform to analyze and thereby to understand the normal stress behavior of complex fluids under LAOS flow We take the Giesekus model as a representative constitutive model and investigate diverse responses of the model We define new dynamic properties corresponding to normal stresses in a similar way to define dynamic moduli from shear stress and examine their behavior with various analyzing tools Experimental data are also compared with model predictions Though it is not yet possible to compare all the predictions due to instrumental limitation the prediction fits well with the experimental data and we hope this study provide a useful framework for further understanding of the nonlinear behavior of complex fluids under LAOS flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
10
Nonlinear behavior of complex fluids under large amplitude
oscillatory shear and squeezing flow
Juha Hwang
Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1580
Email jindols79hotmailcom
Abstract
The purpose of this research is to figure out viscoelastic behavior under large amplitude oscillatory shear (LAOS) and squeezing flow To analyze this behavior we have applied following nonlinear constitutive equations Upper convected Maxwell Giesekus FENE-P Marrucci Leonov Larson and Pom-pom model We analyzed the simulation results by modulus Fourier transform and stress decomposition which distinguishes elastic from viscous contribution to total stress The simulation results were compared with experimental data in other literatures Most constitutive equations predict LAOS behavior qualitatively in shear flow while only Larson model predicts LAOS behavior in squeezing flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
11
Studies on micro-convections induced in a polymer solution heated from above Yasuhiro YAMADA Shinichi SAKURAI
Polymer Science amp Engineering Kyoto Institute of Technology Kyoto Japan
We have reported micro-convections induced by the Soret effect in a polystyrene (PS)dioctylphthalate (DOP) solution under a temperature gradient (heated from below) The Soret effect stands for the fact that the concentration gradient is induced under the applied temperature gradient When temperature gradient is formed in a PSDOP solution PS is accumulated in the cooler side (upper side) by the Soret effect Then the concentrated PS solution undergoes sedimentation because the density of PS is higher than DOP Since this event can take place and result in a convective motion in a considerably thin layer of the solution (say 01 mm thickness) we refer to this as ldquomicro-convectionrdquo If the solvent density is larger than polymer a micro-convection can be induced even when such a solution is heated from above To examine this speculation we conducted experiments on a PStricresylphosphate (TCP) solution heated from above Note that the density of the solvent (TCP) is higher than that of PS Densities are 098 117 and 105 (gcm2) for DOP TCP and PS respectively
The samples used were PS (Mw=200k and MwMn=105) as a solute and TCP as a solvent The weight compositions are in the range of 01999 ~ 50950 The polymer solution was confined in a 05mm thickness layer Temperatures at the top and bottom plates Ttop and Tbot respectively were controlled independently by circulating temperature-regulated water being Ttop and Tbot at 35 and 65 respectively We observed such the polymer solution under a phase-contrast microscope As a result it was found that convection was generated in PSTCP solutions even when heated from above instead of being heated from below Fig 1 shows a typical result of a phase-contrast microscopic observation for the PSTCP sample (50950 composition) heated from below (a) and from above (b) In addition we analyzed dark meshes of convection to obtain brightness of the dark meshes based on which temporal changes in convection activity were examined In Fig2 were shown temporal changes in the brightness of the dark mesh for the PSTCP sample (50950 composition) Some oscillations were found and the brightness finally reached an asymptotic value It is interesting to note that a similar behavior was seen for the case of a PSDOP solution heated from bottom although the direction of the energy input is opposed
---------------------------------------------------------------------------------------------------------------- Corresponding author e-mail d2jyasmailgoonejp TEL 075-724-7864 FAX 075-724-7800
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
12
Development of a mixed-flow rheometer
Jae Hee Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email exodus55snuackr
Abstract This paper is concerned with the development of a mixed-flow rheometer for
determining the viscosity of a highly viscous filled viscoplastic fluid Recently there has been a renewal of interest in mixed-flow of viscoelastic fluid It is difficult to characterize the viscoelastic materials using conventional rheometer such as capillary rotational and compressional rheometers
In this study we develop a new rheometer for analysis of mixed-flow which is the combination of shear and compression mode This rheometer is designed for investigating the different microstructural rearrangement processes by the combination of two-deformation modes It is important to understand the combined-mode within an industrial quality control environment
In this presentation we will summarize the recent method for determination of the properties of viscoelastic systems under mixed-flow and provide a comprehensive mathematical theory for the interpretation of experimental data from the mixed-flow rheometer considering the influence of fluid inertia Also a series of experiments were carried out on a number of viscoelastic systems to confirm the theory
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
13
Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA Tadamine KIMU Hideshige SUZUKI Akihiro NISHIOKA
Tomonori KODA and Susumu IKEDA Department of Polymer Science and Engineering Yamagata University
Ikeda laboratry Yonezawa 992-8510 Japan E-mail dmx13313dipyzyamagata-uacjp
The purpose of this study is to clarify Ferroelectricity and Crystallization in
Poly(vinylidene fluoride)clay nanocomposites The ferroelectoricity in PVDFclay nanocomposites have been examined by measuring the D-E hysteresis loops The composites were also characterized by XRD DSC and TEM The nanocomposites were prepared by using melt compounding method This compounding was carried out by using the Twin Screw Extruder (TECHNOVEL Co Ltd model KZW-30 LD = 45) All samples for measurement were produced by hot press method at 200oC from dried pellet samples
As a result we found that the ferroelectricity can be observed in non-stretched PVDFclay nanocomposites films The PVDF crystal structure in its nanocomposites was similar to β form This results means that blending small amount of nano is one of the way to induce ferroelecticity of PVDF without stretching To clarify the mechanism of the induction ferroelecticity we have estimated lattice spacing of a clay surface by XRD The spacing between negatively charged oxygens on a clay surface is about 257Å which is almost the same spacing of monomer unit of PVDF in all trans chain conformation PVDF monomer on negatively charged clay surface has a permanent electrical dipole moment PVDF crystallites are epitaxially grown up on the clay surface in accordance with surface lattice structure
Acknowledgement We would like to thank for the cooperation of Prof KHAhn and all members of his
Laboratory in Seoul National University (SNU) Korea We would like to thank for providing us with TEM photos of our samples I would also like to thank Mr Namkung Mr Kim and Prof KH Ahn for their valuable comments suggestions support during my stay in Seoul National University (SNU)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
14
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Transient behaviors of immiscible polymer blends under varying flow
field
QUAN CHEN WEI YU CHIXING ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering Shanghai Jiao Tong University Shanghai 200240 P R China
One frequently used method on measuring thixotropy is to perform a loop test In
which changes in the structural level like the break-up and coalescence of the drops
cause measurable thixotropic behavior (Barnes HA (1997)) The flow field in our
experiment is the round trip (RT) test in which an additional opposite trip is added on
traditional thixotropic test The breakup and coalescence mechanics under such a flow
field is discussed here In addition a new model (Yu W and Zhou C (2006)) in which
breakup and coalescence is applied in our analysis
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
7
The effect of viscosity and elasticity on the DOD (Drop-On-Demand) inkjet drop formation
A Young Lee
Byoung Wook Jo Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1879
Email twinklesnuackr
Abstract Inkjet printing is familiar as a method of printing text and images onto substrates
such as paper In the last few years it has been explored as a way of printing electrical and optical devices with the use of specialty inks For a successful inkjet printing to be achieved in this area high resolution patternability is necessary Therefore it is essential to understand the mechanism of ink drop deformation and to reduce the satellite drop which can cause defect in printing
The breakup of viscoelastic jets has been studied by many researchers with a number of dilute and semidilute poly(ethylene oxide) solutions under the gravity Similarly the presence of small amounts of polymer in Newtonian solvents can cause a significant change of the drop-on-demand drop formation This study investigates the effect of viscosity and elasticity on the drop-on-demand drop formation through the use of Newtonian liquids and low viscosity elastic liquids The satellite drop produced by breakup of main drop is easily observed by Newtonian fluids Higher viscosity can suppress this satellite drop formation to some extent and the phenomena become significant when small amount of polymer is added To quantitatively characterize the behavior of drop deformation we compared jet retraction time and breakup time by employing jet stability graphs In jet stability graph the two critical jet speeds can suggest the relative jetting stability in terms of satellite drop generation Finally the effect of imposed pulse shape on drop formation is also studied
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
8
Dielectric Studies of Polymer Chain Dynamics in Polymer Blend
JunTakada HiroshiSasaki YoshiakiMatsushima AkiraKuriyama YumiMatsumiya
TadashiInoue HiroshiWatanabe
Toagosei CoLtd and Institute for Chemical ResearchKyoto University
We examined a relationship between polymer chain dynamics and phase separated
structure in polymer blends The samples used were blends of
polyisoprene(PIPMw=199times10 3 ) and poly-tert-butylstyrene(P-t-BS-HMw=700times10 3
P-t-BS-LMw=160times10 3 ) The blend ratio was PIPP-t-BS=82(wtwt) To discuss the
changes of polymer chain dynamics we investigated the dielectric loss ε rdquo of the blend
samples and pure PIP PIP has type-A dipoles that enable us to dielectrically observe
the global motion of PIP At 30 the global motion of PIP in the blend samples was
slower than that of pure PIP This result suggests that the PIP chains are entangled
with the P-t-BS chains ie mixed in P-t-BS phase and the entanglements retards the
global motion of PIP At 70 the global motion of PIP in blend samples became close
to that of pure PIP suggesting that the PIP chains are not well entangled with P-t-BS
chains at high temperature It has been known that PIPP-t-BS blends exhibit
LCST-type phase behavior Changes of the global motion of PIP in blend samples with
temperature is consistent with this phase behavior
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
9
Normal stress development under large amplitude oscillatory
shear flow
Jung Gun Nam Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email guns2snuackr
Abstract The dynamic response of viscoelastic fluids under large amplitude oscillatory shear (LAOS) has been a subject of long history In recent years there seem to be progresses in this field More advanced instrumentation and new concepts are emerging In the LAOS flow the analysis has been mostly focused on shear stress possibly due to the lack of accurate measurement of normal stress However the normal stress may become larger than shear stress at high strain amplitudes and there are good reasons we need to understand the normal stress behavior As the instrumentation advances it becomes more feasible to get reliable data and this field will be more challenging The purpose of this paper is to develop a research platform to analyze and thereby to understand the normal stress behavior of complex fluids under LAOS flow We take the Giesekus model as a representative constitutive model and investigate diverse responses of the model We define new dynamic properties corresponding to normal stresses in a similar way to define dynamic moduli from shear stress and examine their behavior with various analyzing tools Experimental data are also compared with model predictions Though it is not yet possible to compare all the predictions due to instrumental limitation the prediction fits well with the experimental data and we hope this study provide a useful framework for further understanding of the nonlinear behavior of complex fluids under LAOS flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
10
Nonlinear behavior of complex fluids under large amplitude
oscillatory shear and squeezing flow
Juha Hwang
Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1580
Email jindols79hotmailcom
Abstract
The purpose of this research is to figure out viscoelastic behavior under large amplitude oscillatory shear (LAOS) and squeezing flow To analyze this behavior we have applied following nonlinear constitutive equations Upper convected Maxwell Giesekus FENE-P Marrucci Leonov Larson and Pom-pom model We analyzed the simulation results by modulus Fourier transform and stress decomposition which distinguishes elastic from viscous contribution to total stress The simulation results were compared with experimental data in other literatures Most constitutive equations predict LAOS behavior qualitatively in shear flow while only Larson model predicts LAOS behavior in squeezing flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
11
Studies on micro-convections induced in a polymer solution heated from above Yasuhiro YAMADA Shinichi SAKURAI
Polymer Science amp Engineering Kyoto Institute of Technology Kyoto Japan
We have reported micro-convections induced by the Soret effect in a polystyrene (PS)dioctylphthalate (DOP) solution under a temperature gradient (heated from below) The Soret effect stands for the fact that the concentration gradient is induced under the applied temperature gradient When temperature gradient is formed in a PSDOP solution PS is accumulated in the cooler side (upper side) by the Soret effect Then the concentrated PS solution undergoes sedimentation because the density of PS is higher than DOP Since this event can take place and result in a convective motion in a considerably thin layer of the solution (say 01 mm thickness) we refer to this as ldquomicro-convectionrdquo If the solvent density is larger than polymer a micro-convection can be induced even when such a solution is heated from above To examine this speculation we conducted experiments on a PStricresylphosphate (TCP) solution heated from above Note that the density of the solvent (TCP) is higher than that of PS Densities are 098 117 and 105 (gcm2) for DOP TCP and PS respectively
The samples used were PS (Mw=200k and MwMn=105) as a solute and TCP as a solvent The weight compositions are in the range of 01999 ~ 50950 The polymer solution was confined in a 05mm thickness layer Temperatures at the top and bottom plates Ttop and Tbot respectively were controlled independently by circulating temperature-regulated water being Ttop and Tbot at 35 and 65 respectively We observed such the polymer solution under a phase-contrast microscope As a result it was found that convection was generated in PSTCP solutions even when heated from above instead of being heated from below Fig 1 shows a typical result of a phase-contrast microscopic observation for the PSTCP sample (50950 composition) heated from below (a) and from above (b) In addition we analyzed dark meshes of convection to obtain brightness of the dark meshes based on which temporal changes in convection activity were examined In Fig2 were shown temporal changes in the brightness of the dark mesh for the PSTCP sample (50950 composition) Some oscillations were found and the brightness finally reached an asymptotic value It is interesting to note that a similar behavior was seen for the case of a PSDOP solution heated from bottom although the direction of the energy input is opposed
---------------------------------------------------------------------------------------------------------------- Corresponding author e-mail d2jyasmailgoonejp TEL 075-724-7864 FAX 075-724-7800
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
12
Development of a mixed-flow rheometer
Jae Hee Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email exodus55snuackr
Abstract This paper is concerned with the development of a mixed-flow rheometer for
determining the viscosity of a highly viscous filled viscoplastic fluid Recently there has been a renewal of interest in mixed-flow of viscoelastic fluid It is difficult to characterize the viscoelastic materials using conventional rheometer such as capillary rotational and compressional rheometers
In this study we develop a new rheometer for analysis of mixed-flow which is the combination of shear and compression mode This rheometer is designed for investigating the different microstructural rearrangement processes by the combination of two-deformation modes It is important to understand the combined-mode within an industrial quality control environment
In this presentation we will summarize the recent method for determination of the properties of viscoelastic systems under mixed-flow and provide a comprehensive mathematical theory for the interpretation of experimental data from the mixed-flow rheometer considering the influence of fluid inertia Also a series of experiments were carried out on a number of viscoelastic systems to confirm the theory
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
13
Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA Tadamine KIMU Hideshige SUZUKI Akihiro NISHIOKA
Tomonori KODA and Susumu IKEDA Department of Polymer Science and Engineering Yamagata University
Ikeda laboratry Yonezawa 992-8510 Japan E-mail dmx13313dipyzyamagata-uacjp
The purpose of this study is to clarify Ferroelectricity and Crystallization in
Poly(vinylidene fluoride)clay nanocomposites The ferroelectoricity in PVDFclay nanocomposites have been examined by measuring the D-E hysteresis loops The composites were also characterized by XRD DSC and TEM The nanocomposites were prepared by using melt compounding method This compounding was carried out by using the Twin Screw Extruder (TECHNOVEL Co Ltd model KZW-30 LD = 45) All samples for measurement were produced by hot press method at 200oC from dried pellet samples
As a result we found that the ferroelectricity can be observed in non-stretched PVDFclay nanocomposites films The PVDF crystal structure in its nanocomposites was similar to β form This results means that blending small amount of nano is one of the way to induce ferroelecticity of PVDF without stretching To clarify the mechanism of the induction ferroelecticity we have estimated lattice spacing of a clay surface by XRD The spacing between negatively charged oxygens on a clay surface is about 257Å which is almost the same spacing of monomer unit of PVDF in all trans chain conformation PVDF monomer on negatively charged clay surface has a permanent electrical dipole moment PVDF crystallites are epitaxially grown up on the clay surface in accordance with surface lattice structure
Acknowledgement We would like to thank for the cooperation of Prof KHAhn and all members of his
Laboratory in Seoul National University (SNU) Korea We would like to thank for providing us with TEM photos of our samples I would also like to thank Mr Namkung Mr Kim and Prof KH Ahn for their valuable comments suggestions support during my stay in Seoul National University (SNU)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
14
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
The effect of viscosity and elasticity on the DOD (Drop-On-Demand) inkjet drop formation
A Young Lee
Byoung Wook Jo Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1879
Email twinklesnuackr
Abstract Inkjet printing is familiar as a method of printing text and images onto substrates
such as paper In the last few years it has been explored as a way of printing electrical and optical devices with the use of specialty inks For a successful inkjet printing to be achieved in this area high resolution patternability is necessary Therefore it is essential to understand the mechanism of ink drop deformation and to reduce the satellite drop which can cause defect in printing
The breakup of viscoelastic jets has been studied by many researchers with a number of dilute and semidilute poly(ethylene oxide) solutions under the gravity Similarly the presence of small amounts of polymer in Newtonian solvents can cause a significant change of the drop-on-demand drop formation This study investigates the effect of viscosity and elasticity on the drop-on-demand drop formation through the use of Newtonian liquids and low viscosity elastic liquids The satellite drop produced by breakup of main drop is easily observed by Newtonian fluids Higher viscosity can suppress this satellite drop formation to some extent and the phenomena become significant when small amount of polymer is added To quantitatively characterize the behavior of drop deformation we compared jet retraction time and breakup time by employing jet stability graphs In jet stability graph the two critical jet speeds can suggest the relative jetting stability in terms of satellite drop generation Finally the effect of imposed pulse shape on drop formation is also studied
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
8
Dielectric Studies of Polymer Chain Dynamics in Polymer Blend
JunTakada HiroshiSasaki YoshiakiMatsushima AkiraKuriyama YumiMatsumiya
TadashiInoue HiroshiWatanabe
Toagosei CoLtd and Institute for Chemical ResearchKyoto University
We examined a relationship between polymer chain dynamics and phase separated
structure in polymer blends The samples used were blends of
polyisoprene(PIPMw=199times10 3 ) and poly-tert-butylstyrene(P-t-BS-HMw=700times10 3
P-t-BS-LMw=160times10 3 ) The blend ratio was PIPP-t-BS=82(wtwt) To discuss the
changes of polymer chain dynamics we investigated the dielectric loss ε rdquo of the blend
samples and pure PIP PIP has type-A dipoles that enable us to dielectrically observe
the global motion of PIP At 30 the global motion of PIP in the blend samples was
slower than that of pure PIP This result suggests that the PIP chains are entangled
with the P-t-BS chains ie mixed in P-t-BS phase and the entanglements retards the
global motion of PIP At 70 the global motion of PIP in blend samples became close
to that of pure PIP suggesting that the PIP chains are not well entangled with P-t-BS
chains at high temperature It has been known that PIPP-t-BS blends exhibit
LCST-type phase behavior Changes of the global motion of PIP in blend samples with
temperature is consistent with this phase behavior
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
9
Normal stress development under large amplitude oscillatory
shear flow
Jung Gun Nam Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email guns2snuackr
Abstract The dynamic response of viscoelastic fluids under large amplitude oscillatory shear (LAOS) has been a subject of long history In recent years there seem to be progresses in this field More advanced instrumentation and new concepts are emerging In the LAOS flow the analysis has been mostly focused on shear stress possibly due to the lack of accurate measurement of normal stress However the normal stress may become larger than shear stress at high strain amplitudes and there are good reasons we need to understand the normal stress behavior As the instrumentation advances it becomes more feasible to get reliable data and this field will be more challenging The purpose of this paper is to develop a research platform to analyze and thereby to understand the normal stress behavior of complex fluids under LAOS flow We take the Giesekus model as a representative constitutive model and investigate diverse responses of the model We define new dynamic properties corresponding to normal stresses in a similar way to define dynamic moduli from shear stress and examine their behavior with various analyzing tools Experimental data are also compared with model predictions Though it is not yet possible to compare all the predictions due to instrumental limitation the prediction fits well with the experimental data and we hope this study provide a useful framework for further understanding of the nonlinear behavior of complex fluids under LAOS flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
10
Nonlinear behavior of complex fluids under large amplitude
oscillatory shear and squeezing flow
Juha Hwang
Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1580
Email jindols79hotmailcom
Abstract
The purpose of this research is to figure out viscoelastic behavior under large amplitude oscillatory shear (LAOS) and squeezing flow To analyze this behavior we have applied following nonlinear constitutive equations Upper convected Maxwell Giesekus FENE-P Marrucci Leonov Larson and Pom-pom model We analyzed the simulation results by modulus Fourier transform and stress decomposition which distinguishes elastic from viscous contribution to total stress The simulation results were compared with experimental data in other literatures Most constitutive equations predict LAOS behavior qualitatively in shear flow while only Larson model predicts LAOS behavior in squeezing flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
11
Studies on micro-convections induced in a polymer solution heated from above Yasuhiro YAMADA Shinichi SAKURAI
Polymer Science amp Engineering Kyoto Institute of Technology Kyoto Japan
We have reported micro-convections induced by the Soret effect in a polystyrene (PS)dioctylphthalate (DOP) solution under a temperature gradient (heated from below) The Soret effect stands for the fact that the concentration gradient is induced under the applied temperature gradient When temperature gradient is formed in a PSDOP solution PS is accumulated in the cooler side (upper side) by the Soret effect Then the concentrated PS solution undergoes sedimentation because the density of PS is higher than DOP Since this event can take place and result in a convective motion in a considerably thin layer of the solution (say 01 mm thickness) we refer to this as ldquomicro-convectionrdquo If the solvent density is larger than polymer a micro-convection can be induced even when such a solution is heated from above To examine this speculation we conducted experiments on a PStricresylphosphate (TCP) solution heated from above Note that the density of the solvent (TCP) is higher than that of PS Densities are 098 117 and 105 (gcm2) for DOP TCP and PS respectively
The samples used were PS (Mw=200k and MwMn=105) as a solute and TCP as a solvent The weight compositions are in the range of 01999 ~ 50950 The polymer solution was confined in a 05mm thickness layer Temperatures at the top and bottom plates Ttop and Tbot respectively were controlled independently by circulating temperature-regulated water being Ttop and Tbot at 35 and 65 respectively We observed such the polymer solution under a phase-contrast microscope As a result it was found that convection was generated in PSTCP solutions even when heated from above instead of being heated from below Fig 1 shows a typical result of a phase-contrast microscopic observation for the PSTCP sample (50950 composition) heated from below (a) and from above (b) In addition we analyzed dark meshes of convection to obtain brightness of the dark meshes based on which temporal changes in convection activity were examined In Fig2 were shown temporal changes in the brightness of the dark mesh for the PSTCP sample (50950 composition) Some oscillations were found and the brightness finally reached an asymptotic value It is interesting to note that a similar behavior was seen for the case of a PSDOP solution heated from bottom although the direction of the energy input is opposed
---------------------------------------------------------------------------------------------------------------- Corresponding author e-mail d2jyasmailgoonejp TEL 075-724-7864 FAX 075-724-7800
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
12
Development of a mixed-flow rheometer
Jae Hee Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email exodus55snuackr
Abstract This paper is concerned with the development of a mixed-flow rheometer for
determining the viscosity of a highly viscous filled viscoplastic fluid Recently there has been a renewal of interest in mixed-flow of viscoelastic fluid It is difficult to characterize the viscoelastic materials using conventional rheometer such as capillary rotational and compressional rheometers
In this study we develop a new rheometer for analysis of mixed-flow which is the combination of shear and compression mode This rheometer is designed for investigating the different microstructural rearrangement processes by the combination of two-deformation modes It is important to understand the combined-mode within an industrial quality control environment
In this presentation we will summarize the recent method for determination of the properties of viscoelastic systems under mixed-flow and provide a comprehensive mathematical theory for the interpretation of experimental data from the mixed-flow rheometer considering the influence of fluid inertia Also a series of experiments were carried out on a number of viscoelastic systems to confirm the theory
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
13
Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA Tadamine KIMU Hideshige SUZUKI Akihiro NISHIOKA
Tomonori KODA and Susumu IKEDA Department of Polymer Science and Engineering Yamagata University
Ikeda laboratry Yonezawa 992-8510 Japan E-mail dmx13313dipyzyamagata-uacjp
The purpose of this study is to clarify Ferroelectricity and Crystallization in
Poly(vinylidene fluoride)clay nanocomposites The ferroelectoricity in PVDFclay nanocomposites have been examined by measuring the D-E hysteresis loops The composites were also characterized by XRD DSC and TEM The nanocomposites were prepared by using melt compounding method This compounding was carried out by using the Twin Screw Extruder (TECHNOVEL Co Ltd model KZW-30 LD = 45) All samples for measurement were produced by hot press method at 200oC from dried pellet samples
As a result we found that the ferroelectricity can be observed in non-stretched PVDFclay nanocomposites films The PVDF crystal structure in its nanocomposites was similar to β form This results means that blending small amount of nano is one of the way to induce ferroelecticity of PVDF without stretching To clarify the mechanism of the induction ferroelecticity we have estimated lattice spacing of a clay surface by XRD The spacing between negatively charged oxygens on a clay surface is about 257Å which is almost the same spacing of monomer unit of PVDF in all trans chain conformation PVDF monomer on negatively charged clay surface has a permanent electrical dipole moment PVDF crystallites are epitaxially grown up on the clay surface in accordance with surface lattice structure
Acknowledgement We would like to thank for the cooperation of Prof KHAhn and all members of his
Laboratory in Seoul National University (SNU) Korea We would like to thank for providing us with TEM photos of our samples I would also like to thank Mr Namkung Mr Kim and Prof KH Ahn for their valuable comments suggestions support during my stay in Seoul National University (SNU)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
14
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Dielectric Studies of Polymer Chain Dynamics in Polymer Blend
JunTakada HiroshiSasaki YoshiakiMatsushima AkiraKuriyama YumiMatsumiya
TadashiInoue HiroshiWatanabe
Toagosei CoLtd and Institute for Chemical ResearchKyoto University
We examined a relationship between polymer chain dynamics and phase separated
structure in polymer blends The samples used were blends of
polyisoprene(PIPMw=199times10 3 ) and poly-tert-butylstyrene(P-t-BS-HMw=700times10 3
P-t-BS-LMw=160times10 3 ) The blend ratio was PIPP-t-BS=82(wtwt) To discuss the
changes of polymer chain dynamics we investigated the dielectric loss ε rdquo of the blend
samples and pure PIP PIP has type-A dipoles that enable us to dielectrically observe
the global motion of PIP At 30 the global motion of PIP in the blend samples was
slower than that of pure PIP This result suggests that the PIP chains are entangled
with the P-t-BS chains ie mixed in P-t-BS phase and the entanglements retards the
global motion of PIP At 70 the global motion of PIP in blend samples became close
to that of pure PIP suggesting that the PIP chains are not well entangled with P-t-BS
chains at high temperature It has been known that PIPP-t-BS blends exhibit
LCST-type phase behavior Changes of the global motion of PIP in blend samples with
temperature is consistent with this phase behavior
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
9
Normal stress development under large amplitude oscillatory
shear flow
Jung Gun Nam Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email guns2snuackr
Abstract The dynamic response of viscoelastic fluids under large amplitude oscillatory shear (LAOS) has been a subject of long history In recent years there seem to be progresses in this field More advanced instrumentation and new concepts are emerging In the LAOS flow the analysis has been mostly focused on shear stress possibly due to the lack of accurate measurement of normal stress However the normal stress may become larger than shear stress at high strain amplitudes and there are good reasons we need to understand the normal stress behavior As the instrumentation advances it becomes more feasible to get reliable data and this field will be more challenging The purpose of this paper is to develop a research platform to analyze and thereby to understand the normal stress behavior of complex fluids under LAOS flow We take the Giesekus model as a representative constitutive model and investigate diverse responses of the model We define new dynamic properties corresponding to normal stresses in a similar way to define dynamic moduli from shear stress and examine their behavior with various analyzing tools Experimental data are also compared with model predictions Though it is not yet possible to compare all the predictions due to instrumental limitation the prediction fits well with the experimental data and we hope this study provide a useful framework for further understanding of the nonlinear behavior of complex fluids under LAOS flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
10
Nonlinear behavior of complex fluids under large amplitude
oscillatory shear and squeezing flow
Juha Hwang
Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1580
Email jindols79hotmailcom
Abstract
The purpose of this research is to figure out viscoelastic behavior under large amplitude oscillatory shear (LAOS) and squeezing flow To analyze this behavior we have applied following nonlinear constitutive equations Upper convected Maxwell Giesekus FENE-P Marrucci Leonov Larson and Pom-pom model We analyzed the simulation results by modulus Fourier transform and stress decomposition which distinguishes elastic from viscous contribution to total stress The simulation results were compared with experimental data in other literatures Most constitutive equations predict LAOS behavior qualitatively in shear flow while only Larson model predicts LAOS behavior in squeezing flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
11
Studies on micro-convections induced in a polymer solution heated from above Yasuhiro YAMADA Shinichi SAKURAI
Polymer Science amp Engineering Kyoto Institute of Technology Kyoto Japan
We have reported micro-convections induced by the Soret effect in a polystyrene (PS)dioctylphthalate (DOP) solution under a temperature gradient (heated from below) The Soret effect stands for the fact that the concentration gradient is induced under the applied temperature gradient When temperature gradient is formed in a PSDOP solution PS is accumulated in the cooler side (upper side) by the Soret effect Then the concentrated PS solution undergoes sedimentation because the density of PS is higher than DOP Since this event can take place and result in a convective motion in a considerably thin layer of the solution (say 01 mm thickness) we refer to this as ldquomicro-convectionrdquo If the solvent density is larger than polymer a micro-convection can be induced even when such a solution is heated from above To examine this speculation we conducted experiments on a PStricresylphosphate (TCP) solution heated from above Note that the density of the solvent (TCP) is higher than that of PS Densities are 098 117 and 105 (gcm2) for DOP TCP and PS respectively
The samples used were PS (Mw=200k and MwMn=105) as a solute and TCP as a solvent The weight compositions are in the range of 01999 ~ 50950 The polymer solution was confined in a 05mm thickness layer Temperatures at the top and bottom plates Ttop and Tbot respectively were controlled independently by circulating temperature-regulated water being Ttop and Tbot at 35 and 65 respectively We observed such the polymer solution under a phase-contrast microscope As a result it was found that convection was generated in PSTCP solutions even when heated from above instead of being heated from below Fig 1 shows a typical result of a phase-contrast microscopic observation for the PSTCP sample (50950 composition) heated from below (a) and from above (b) In addition we analyzed dark meshes of convection to obtain brightness of the dark meshes based on which temporal changes in convection activity were examined In Fig2 were shown temporal changes in the brightness of the dark mesh for the PSTCP sample (50950 composition) Some oscillations were found and the brightness finally reached an asymptotic value It is interesting to note that a similar behavior was seen for the case of a PSDOP solution heated from bottom although the direction of the energy input is opposed
---------------------------------------------------------------------------------------------------------------- Corresponding author e-mail d2jyasmailgoonejp TEL 075-724-7864 FAX 075-724-7800
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
12
Development of a mixed-flow rheometer
Jae Hee Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email exodus55snuackr
Abstract This paper is concerned with the development of a mixed-flow rheometer for
determining the viscosity of a highly viscous filled viscoplastic fluid Recently there has been a renewal of interest in mixed-flow of viscoelastic fluid It is difficult to characterize the viscoelastic materials using conventional rheometer such as capillary rotational and compressional rheometers
In this study we develop a new rheometer for analysis of mixed-flow which is the combination of shear and compression mode This rheometer is designed for investigating the different microstructural rearrangement processes by the combination of two-deformation modes It is important to understand the combined-mode within an industrial quality control environment
In this presentation we will summarize the recent method for determination of the properties of viscoelastic systems under mixed-flow and provide a comprehensive mathematical theory for the interpretation of experimental data from the mixed-flow rheometer considering the influence of fluid inertia Also a series of experiments were carried out on a number of viscoelastic systems to confirm the theory
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
13
Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA Tadamine KIMU Hideshige SUZUKI Akihiro NISHIOKA
Tomonori KODA and Susumu IKEDA Department of Polymer Science and Engineering Yamagata University
Ikeda laboratry Yonezawa 992-8510 Japan E-mail dmx13313dipyzyamagata-uacjp
The purpose of this study is to clarify Ferroelectricity and Crystallization in
Poly(vinylidene fluoride)clay nanocomposites The ferroelectoricity in PVDFclay nanocomposites have been examined by measuring the D-E hysteresis loops The composites were also characterized by XRD DSC and TEM The nanocomposites were prepared by using melt compounding method This compounding was carried out by using the Twin Screw Extruder (TECHNOVEL Co Ltd model KZW-30 LD = 45) All samples for measurement were produced by hot press method at 200oC from dried pellet samples
As a result we found that the ferroelectricity can be observed in non-stretched PVDFclay nanocomposites films The PVDF crystal structure in its nanocomposites was similar to β form This results means that blending small amount of nano is one of the way to induce ferroelecticity of PVDF without stretching To clarify the mechanism of the induction ferroelecticity we have estimated lattice spacing of a clay surface by XRD The spacing between negatively charged oxygens on a clay surface is about 257Å which is almost the same spacing of monomer unit of PVDF in all trans chain conformation PVDF monomer on negatively charged clay surface has a permanent electrical dipole moment PVDF crystallites are epitaxially grown up on the clay surface in accordance with surface lattice structure
Acknowledgement We would like to thank for the cooperation of Prof KHAhn and all members of his
Laboratory in Seoul National University (SNU) Korea We would like to thank for providing us with TEM photos of our samples I would also like to thank Mr Namkung Mr Kim and Prof KH Ahn for their valuable comments suggestions support during my stay in Seoul National University (SNU)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
14
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Normal stress development under large amplitude oscillatory
shear flow
Jung Gun Nam Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email guns2snuackr
Abstract The dynamic response of viscoelastic fluids under large amplitude oscillatory shear (LAOS) has been a subject of long history In recent years there seem to be progresses in this field More advanced instrumentation and new concepts are emerging In the LAOS flow the analysis has been mostly focused on shear stress possibly due to the lack of accurate measurement of normal stress However the normal stress may become larger than shear stress at high strain amplitudes and there are good reasons we need to understand the normal stress behavior As the instrumentation advances it becomes more feasible to get reliable data and this field will be more challenging The purpose of this paper is to develop a research platform to analyze and thereby to understand the normal stress behavior of complex fluids under LAOS flow We take the Giesekus model as a representative constitutive model and investigate diverse responses of the model We define new dynamic properties corresponding to normal stresses in a similar way to define dynamic moduli from shear stress and examine their behavior with various analyzing tools Experimental data are also compared with model predictions Though it is not yet possible to compare all the predictions due to instrumental limitation the prediction fits well with the experimental data and we hope this study provide a useful framework for further understanding of the nonlinear behavior of complex fluids under LAOS flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
10
Nonlinear behavior of complex fluids under large amplitude
oscillatory shear and squeezing flow
Juha Hwang
Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1580
Email jindols79hotmailcom
Abstract
The purpose of this research is to figure out viscoelastic behavior under large amplitude oscillatory shear (LAOS) and squeezing flow To analyze this behavior we have applied following nonlinear constitutive equations Upper convected Maxwell Giesekus FENE-P Marrucci Leonov Larson and Pom-pom model We analyzed the simulation results by modulus Fourier transform and stress decomposition which distinguishes elastic from viscous contribution to total stress The simulation results were compared with experimental data in other literatures Most constitutive equations predict LAOS behavior qualitatively in shear flow while only Larson model predicts LAOS behavior in squeezing flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
11
Studies on micro-convections induced in a polymer solution heated from above Yasuhiro YAMADA Shinichi SAKURAI
Polymer Science amp Engineering Kyoto Institute of Technology Kyoto Japan
We have reported micro-convections induced by the Soret effect in a polystyrene (PS)dioctylphthalate (DOP) solution under a temperature gradient (heated from below) The Soret effect stands for the fact that the concentration gradient is induced under the applied temperature gradient When temperature gradient is formed in a PSDOP solution PS is accumulated in the cooler side (upper side) by the Soret effect Then the concentrated PS solution undergoes sedimentation because the density of PS is higher than DOP Since this event can take place and result in a convective motion in a considerably thin layer of the solution (say 01 mm thickness) we refer to this as ldquomicro-convectionrdquo If the solvent density is larger than polymer a micro-convection can be induced even when such a solution is heated from above To examine this speculation we conducted experiments on a PStricresylphosphate (TCP) solution heated from above Note that the density of the solvent (TCP) is higher than that of PS Densities are 098 117 and 105 (gcm2) for DOP TCP and PS respectively
The samples used were PS (Mw=200k and MwMn=105) as a solute and TCP as a solvent The weight compositions are in the range of 01999 ~ 50950 The polymer solution was confined in a 05mm thickness layer Temperatures at the top and bottom plates Ttop and Tbot respectively were controlled independently by circulating temperature-regulated water being Ttop and Tbot at 35 and 65 respectively We observed such the polymer solution under a phase-contrast microscope As a result it was found that convection was generated in PSTCP solutions even when heated from above instead of being heated from below Fig 1 shows a typical result of a phase-contrast microscopic observation for the PSTCP sample (50950 composition) heated from below (a) and from above (b) In addition we analyzed dark meshes of convection to obtain brightness of the dark meshes based on which temporal changes in convection activity were examined In Fig2 were shown temporal changes in the brightness of the dark mesh for the PSTCP sample (50950 composition) Some oscillations were found and the brightness finally reached an asymptotic value It is interesting to note that a similar behavior was seen for the case of a PSDOP solution heated from bottom although the direction of the energy input is opposed
---------------------------------------------------------------------------------------------------------------- Corresponding author e-mail d2jyasmailgoonejp TEL 075-724-7864 FAX 075-724-7800
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
12
Development of a mixed-flow rheometer
Jae Hee Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email exodus55snuackr
Abstract This paper is concerned with the development of a mixed-flow rheometer for
determining the viscosity of a highly viscous filled viscoplastic fluid Recently there has been a renewal of interest in mixed-flow of viscoelastic fluid It is difficult to characterize the viscoelastic materials using conventional rheometer such as capillary rotational and compressional rheometers
In this study we develop a new rheometer for analysis of mixed-flow which is the combination of shear and compression mode This rheometer is designed for investigating the different microstructural rearrangement processes by the combination of two-deformation modes It is important to understand the combined-mode within an industrial quality control environment
In this presentation we will summarize the recent method for determination of the properties of viscoelastic systems under mixed-flow and provide a comprehensive mathematical theory for the interpretation of experimental data from the mixed-flow rheometer considering the influence of fluid inertia Also a series of experiments were carried out on a number of viscoelastic systems to confirm the theory
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
13
Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA Tadamine KIMU Hideshige SUZUKI Akihiro NISHIOKA
Tomonori KODA and Susumu IKEDA Department of Polymer Science and Engineering Yamagata University
Ikeda laboratry Yonezawa 992-8510 Japan E-mail dmx13313dipyzyamagata-uacjp
The purpose of this study is to clarify Ferroelectricity and Crystallization in
Poly(vinylidene fluoride)clay nanocomposites The ferroelectoricity in PVDFclay nanocomposites have been examined by measuring the D-E hysteresis loops The composites were also characterized by XRD DSC and TEM The nanocomposites were prepared by using melt compounding method This compounding was carried out by using the Twin Screw Extruder (TECHNOVEL Co Ltd model KZW-30 LD = 45) All samples for measurement were produced by hot press method at 200oC from dried pellet samples
As a result we found that the ferroelectricity can be observed in non-stretched PVDFclay nanocomposites films The PVDF crystal structure in its nanocomposites was similar to β form This results means that blending small amount of nano is one of the way to induce ferroelecticity of PVDF without stretching To clarify the mechanism of the induction ferroelecticity we have estimated lattice spacing of a clay surface by XRD The spacing between negatively charged oxygens on a clay surface is about 257Å which is almost the same spacing of monomer unit of PVDF in all trans chain conformation PVDF monomer on negatively charged clay surface has a permanent electrical dipole moment PVDF crystallites are epitaxially grown up on the clay surface in accordance with surface lattice structure
Acknowledgement We would like to thank for the cooperation of Prof KHAhn and all members of his
Laboratory in Seoul National University (SNU) Korea We would like to thank for providing us with TEM photos of our samples I would also like to thank Mr Namkung Mr Kim and Prof KH Ahn for their valuable comments suggestions support during my stay in Seoul National University (SNU)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
14
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Nonlinear behavior of complex fluids under large amplitude
oscillatory shear and squeezing flow
Juha Hwang
Kyung Hyun Ahn Seung Jong Lee School of Chemical and Biological Engineering Seoul National University
Seoul Korea TEL 82-2-880-1580
Email jindols79hotmailcom
Abstract
The purpose of this research is to figure out viscoelastic behavior under large amplitude oscillatory shear (LAOS) and squeezing flow To analyze this behavior we have applied following nonlinear constitutive equations Upper convected Maxwell Giesekus FENE-P Marrucci Leonov Larson and Pom-pom model We analyzed the simulation results by modulus Fourier transform and stress decomposition which distinguishes elastic from viscous contribution to total stress The simulation results were compared with experimental data in other literatures Most constitutive equations predict LAOS behavior qualitatively in shear flow while only Larson model predicts LAOS behavior in squeezing flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
11
Studies on micro-convections induced in a polymer solution heated from above Yasuhiro YAMADA Shinichi SAKURAI
Polymer Science amp Engineering Kyoto Institute of Technology Kyoto Japan
We have reported micro-convections induced by the Soret effect in a polystyrene (PS)dioctylphthalate (DOP) solution under a temperature gradient (heated from below) The Soret effect stands for the fact that the concentration gradient is induced under the applied temperature gradient When temperature gradient is formed in a PSDOP solution PS is accumulated in the cooler side (upper side) by the Soret effect Then the concentrated PS solution undergoes sedimentation because the density of PS is higher than DOP Since this event can take place and result in a convective motion in a considerably thin layer of the solution (say 01 mm thickness) we refer to this as ldquomicro-convectionrdquo If the solvent density is larger than polymer a micro-convection can be induced even when such a solution is heated from above To examine this speculation we conducted experiments on a PStricresylphosphate (TCP) solution heated from above Note that the density of the solvent (TCP) is higher than that of PS Densities are 098 117 and 105 (gcm2) for DOP TCP and PS respectively
The samples used were PS (Mw=200k and MwMn=105) as a solute and TCP as a solvent The weight compositions are in the range of 01999 ~ 50950 The polymer solution was confined in a 05mm thickness layer Temperatures at the top and bottom plates Ttop and Tbot respectively were controlled independently by circulating temperature-regulated water being Ttop and Tbot at 35 and 65 respectively We observed such the polymer solution under a phase-contrast microscope As a result it was found that convection was generated in PSTCP solutions even when heated from above instead of being heated from below Fig 1 shows a typical result of a phase-contrast microscopic observation for the PSTCP sample (50950 composition) heated from below (a) and from above (b) In addition we analyzed dark meshes of convection to obtain brightness of the dark meshes based on which temporal changes in convection activity were examined In Fig2 were shown temporal changes in the brightness of the dark mesh for the PSTCP sample (50950 composition) Some oscillations were found and the brightness finally reached an asymptotic value It is interesting to note that a similar behavior was seen for the case of a PSDOP solution heated from bottom although the direction of the energy input is opposed
---------------------------------------------------------------------------------------------------------------- Corresponding author e-mail d2jyasmailgoonejp TEL 075-724-7864 FAX 075-724-7800
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
12
Development of a mixed-flow rheometer
Jae Hee Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email exodus55snuackr
Abstract This paper is concerned with the development of a mixed-flow rheometer for
determining the viscosity of a highly viscous filled viscoplastic fluid Recently there has been a renewal of interest in mixed-flow of viscoelastic fluid It is difficult to characterize the viscoelastic materials using conventional rheometer such as capillary rotational and compressional rheometers
In this study we develop a new rheometer for analysis of mixed-flow which is the combination of shear and compression mode This rheometer is designed for investigating the different microstructural rearrangement processes by the combination of two-deformation modes It is important to understand the combined-mode within an industrial quality control environment
In this presentation we will summarize the recent method for determination of the properties of viscoelastic systems under mixed-flow and provide a comprehensive mathematical theory for the interpretation of experimental data from the mixed-flow rheometer considering the influence of fluid inertia Also a series of experiments were carried out on a number of viscoelastic systems to confirm the theory
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
13
Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA Tadamine KIMU Hideshige SUZUKI Akihiro NISHIOKA
Tomonori KODA and Susumu IKEDA Department of Polymer Science and Engineering Yamagata University
Ikeda laboratry Yonezawa 992-8510 Japan E-mail dmx13313dipyzyamagata-uacjp
The purpose of this study is to clarify Ferroelectricity and Crystallization in
Poly(vinylidene fluoride)clay nanocomposites The ferroelectoricity in PVDFclay nanocomposites have been examined by measuring the D-E hysteresis loops The composites were also characterized by XRD DSC and TEM The nanocomposites were prepared by using melt compounding method This compounding was carried out by using the Twin Screw Extruder (TECHNOVEL Co Ltd model KZW-30 LD = 45) All samples for measurement were produced by hot press method at 200oC from dried pellet samples
As a result we found that the ferroelectricity can be observed in non-stretched PVDFclay nanocomposites films The PVDF crystal structure in its nanocomposites was similar to β form This results means that blending small amount of nano is one of the way to induce ferroelecticity of PVDF without stretching To clarify the mechanism of the induction ferroelecticity we have estimated lattice spacing of a clay surface by XRD The spacing between negatively charged oxygens on a clay surface is about 257Å which is almost the same spacing of monomer unit of PVDF in all trans chain conformation PVDF monomer on negatively charged clay surface has a permanent electrical dipole moment PVDF crystallites are epitaxially grown up on the clay surface in accordance with surface lattice structure
Acknowledgement We would like to thank for the cooperation of Prof KHAhn and all members of his
Laboratory in Seoul National University (SNU) Korea We would like to thank for providing us with TEM photos of our samples I would also like to thank Mr Namkung Mr Kim and Prof KH Ahn for their valuable comments suggestions support during my stay in Seoul National University (SNU)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
14
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Studies on micro-convections induced in a polymer solution heated from above Yasuhiro YAMADA Shinichi SAKURAI
Polymer Science amp Engineering Kyoto Institute of Technology Kyoto Japan
We have reported micro-convections induced by the Soret effect in a polystyrene (PS)dioctylphthalate (DOP) solution under a temperature gradient (heated from below) The Soret effect stands for the fact that the concentration gradient is induced under the applied temperature gradient When temperature gradient is formed in a PSDOP solution PS is accumulated in the cooler side (upper side) by the Soret effect Then the concentrated PS solution undergoes sedimentation because the density of PS is higher than DOP Since this event can take place and result in a convective motion in a considerably thin layer of the solution (say 01 mm thickness) we refer to this as ldquomicro-convectionrdquo If the solvent density is larger than polymer a micro-convection can be induced even when such a solution is heated from above To examine this speculation we conducted experiments on a PStricresylphosphate (TCP) solution heated from above Note that the density of the solvent (TCP) is higher than that of PS Densities are 098 117 and 105 (gcm2) for DOP TCP and PS respectively
The samples used were PS (Mw=200k and MwMn=105) as a solute and TCP as a solvent The weight compositions are in the range of 01999 ~ 50950 The polymer solution was confined in a 05mm thickness layer Temperatures at the top and bottom plates Ttop and Tbot respectively were controlled independently by circulating temperature-regulated water being Ttop and Tbot at 35 and 65 respectively We observed such the polymer solution under a phase-contrast microscope As a result it was found that convection was generated in PSTCP solutions even when heated from above instead of being heated from below Fig 1 shows a typical result of a phase-contrast microscopic observation for the PSTCP sample (50950 composition) heated from below (a) and from above (b) In addition we analyzed dark meshes of convection to obtain brightness of the dark meshes based on which temporal changes in convection activity were examined In Fig2 were shown temporal changes in the brightness of the dark mesh for the PSTCP sample (50950 composition) Some oscillations were found and the brightness finally reached an asymptotic value It is interesting to note that a similar behavior was seen for the case of a PSDOP solution heated from bottom although the direction of the energy input is opposed
---------------------------------------------------------------------------------------------------------------- Corresponding author e-mail d2jyasmailgoonejp TEL 075-724-7864 FAX 075-724-7800
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
12
Development of a mixed-flow rheometer
Jae Hee Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email exodus55snuackr
Abstract This paper is concerned with the development of a mixed-flow rheometer for
determining the viscosity of a highly viscous filled viscoplastic fluid Recently there has been a renewal of interest in mixed-flow of viscoelastic fluid It is difficult to characterize the viscoelastic materials using conventional rheometer such as capillary rotational and compressional rheometers
In this study we develop a new rheometer for analysis of mixed-flow which is the combination of shear and compression mode This rheometer is designed for investigating the different microstructural rearrangement processes by the combination of two-deformation modes It is important to understand the combined-mode within an industrial quality control environment
In this presentation we will summarize the recent method for determination of the properties of viscoelastic systems under mixed-flow and provide a comprehensive mathematical theory for the interpretation of experimental data from the mixed-flow rheometer considering the influence of fluid inertia Also a series of experiments were carried out on a number of viscoelastic systems to confirm the theory
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
13
Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA Tadamine KIMU Hideshige SUZUKI Akihiro NISHIOKA
Tomonori KODA and Susumu IKEDA Department of Polymer Science and Engineering Yamagata University
Ikeda laboratry Yonezawa 992-8510 Japan E-mail dmx13313dipyzyamagata-uacjp
The purpose of this study is to clarify Ferroelectricity and Crystallization in
Poly(vinylidene fluoride)clay nanocomposites The ferroelectoricity in PVDFclay nanocomposites have been examined by measuring the D-E hysteresis loops The composites were also characterized by XRD DSC and TEM The nanocomposites were prepared by using melt compounding method This compounding was carried out by using the Twin Screw Extruder (TECHNOVEL Co Ltd model KZW-30 LD = 45) All samples for measurement were produced by hot press method at 200oC from dried pellet samples
As a result we found that the ferroelectricity can be observed in non-stretched PVDFclay nanocomposites films The PVDF crystal structure in its nanocomposites was similar to β form This results means that blending small amount of nano is one of the way to induce ferroelecticity of PVDF without stretching To clarify the mechanism of the induction ferroelecticity we have estimated lattice spacing of a clay surface by XRD The spacing between negatively charged oxygens on a clay surface is about 257Å which is almost the same spacing of monomer unit of PVDF in all trans chain conformation PVDF monomer on negatively charged clay surface has a permanent electrical dipole moment PVDF crystallites are epitaxially grown up on the clay surface in accordance with surface lattice structure
Acknowledgement We would like to thank for the cooperation of Prof KHAhn and all members of his
Laboratory in Seoul National University (SNU) Korea We would like to thank for providing us with TEM photos of our samples I would also like to thank Mr Namkung Mr Kim and Prof KH Ahn for their valuable comments suggestions support during my stay in Seoul National University (SNU)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
14
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Development of a mixed-flow rheometer
Jae Hee Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email exodus55snuackr
Abstract This paper is concerned with the development of a mixed-flow rheometer for
determining the viscosity of a highly viscous filled viscoplastic fluid Recently there has been a renewal of interest in mixed-flow of viscoelastic fluid It is difficult to characterize the viscoelastic materials using conventional rheometer such as capillary rotational and compressional rheometers
In this study we develop a new rheometer for analysis of mixed-flow which is the combination of shear and compression mode This rheometer is designed for investigating the different microstructural rearrangement processes by the combination of two-deformation modes It is important to understand the combined-mode within an industrial quality control environment
In this presentation we will summarize the recent method for determination of the properties of viscoelastic systems under mixed-flow and provide a comprehensive mathematical theory for the interpretation of experimental data from the mixed-flow rheometer considering the influence of fluid inertia Also a series of experiments were carried out on a number of viscoelastic systems to confirm the theory
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
13
Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA Tadamine KIMU Hideshige SUZUKI Akihiro NISHIOKA
Tomonori KODA and Susumu IKEDA Department of Polymer Science and Engineering Yamagata University
Ikeda laboratry Yonezawa 992-8510 Japan E-mail dmx13313dipyzyamagata-uacjp
The purpose of this study is to clarify Ferroelectricity and Crystallization in
Poly(vinylidene fluoride)clay nanocomposites The ferroelectoricity in PVDFclay nanocomposites have been examined by measuring the D-E hysteresis loops The composites were also characterized by XRD DSC and TEM The nanocomposites were prepared by using melt compounding method This compounding was carried out by using the Twin Screw Extruder (TECHNOVEL Co Ltd model KZW-30 LD = 45) All samples for measurement were produced by hot press method at 200oC from dried pellet samples
As a result we found that the ferroelectricity can be observed in non-stretched PVDFclay nanocomposites films The PVDF crystal structure in its nanocomposites was similar to β form This results means that blending small amount of nano is one of the way to induce ferroelecticity of PVDF without stretching To clarify the mechanism of the induction ferroelecticity we have estimated lattice spacing of a clay surface by XRD The spacing between negatively charged oxygens on a clay surface is about 257Å which is almost the same spacing of monomer unit of PVDF in all trans chain conformation PVDF monomer on negatively charged clay surface has a permanent electrical dipole moment PVDF crystallites are epitaxially grown up on the clay surface in accordance with surface lattice structure
Acknowledgement We would like to thank for the cooperation of Prof KHAhn and all members of his
Laboratory in Seoul National University (SNU) Korea We would like to thank for providing us with TEM photos of our samples I would also like to thank Mr Namkung Mr Kim and Prof KH Ahn for their valuable comments suggestions support during my stay in Seoul National University (SNU)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
14
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Ferroelectricity and Crystallization in Poly(vinylidene fluoride)clay nanocomposites
Eiji YAMADA Tadamine KIMU Hideshige SUZUKI Akihiro NISHIOKA
Tomonori KODA and Susumu IKEDA Department of Polymer Science and Engineering Yamagata University
Ikeda laboratry Yonezawa 992-8510 Japan E-mail dmx13313dipyzyamagata-uacjp
The purpose of this study is to clarify Ferroelectricity and Crystallization in
Poly(vinylidene fluoride)clay nanocomposites The ferroelectoricity in PVDFclay nanocomposites have been examined by measuring the D-E hysteresis loops The composites were also characterized by XRD DSC and TEM The nanocomposites were prepared by using melt compounding method This compounding was carried out by using the Twin Screw Extruder (TECHNOVEL Co Ltd model KZW-30 LD = 45) All samples for measurement were produced by hot press method at 200oC from dried pellet samples
As a result we found that the ferroelectricity can be observed in non-stretched PVDFclay nanocomposites films The PVDF crystal structure in its nanocomposites was similar to β form This results means that blending small amount of nano is one of the way to induce ferroelecticity of PVDF without stretching To clarify the mechanism of the induction ferroelecticity we have estimated lattice spacing of a clay surface by XRD The spacing between negatively charged oxygens on a clay surface is about 257Å which is almost the same spacing of monomer unit of PVDF in all trans chain conformation PVDF monomer on negatively charged clay surface has a permanent electrical dipole moment PVDF crystallites are epitaxially grown up on the clay surface in accordance with surface lattice structure
Acknowledgement We would like to thank for the cooperation of Prof KHAhn and all members of his
Laboratory in Seoul National University (SNU) Korea We would like to thank for providing us with TEM photos of our samples I would also like to thank Mr Namkung Mr Kim and Prof KH Ahn for their valuable comments suggestions support during my stay in Seoul National University (SNU)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
14
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Rheological behaviors of polyolefincalcium carbonate nanocomposites
Hyung Tag Lim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1879 Email lht0717snuackr
Abstract Recently melt-extensional properties of polymer nanocomposties which is closely
related to the melt strength of polymer has been recognized as one of important parameters in various processing methods such as film processing thermoforming blow molding and foaming The rheological behaviors of the polymer nanocomposties were investigated with special attentions to effects of modified precipitated calcium carbonate (CPCC) and other nanoparticles on extensional behaviors of polyolefin (PP and PE) In our studies we introduced a certain amounts of modified calcium carbonates into polyolefin by melt-blending and meanwhile controlled the interaction between polymer and calcium carbonates via choice of compatibilizers It was shown that the increases in extensional properties depended on types and amounts of surface modifiers chosen and the compatibility between polymer matrix and modified nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
15
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
The Effect of Shear Flow on the Reaction of POE with
Peroxide
Jianye LIU Wei YU Chixing ZHOU
Advanced Rheology Institute Department of Polymer Science and Engineering
Shanghai Jiao Tong University Shanghai 200240 P R China
The degrading behaviors of four kinds of melt polyolefin elastomers (POE) at
presence of dicumyl peroxides (DCP) were evaluated at elevated temperature by
parallel plate rheometer For the cases of poly(ethylene-co-α-octene) (EO) and
poly(ethylene-co-α-butene) (EB) in oscillatory shear flow at high frequencies the
degradation occurred even with the strains applied within the linear viscoelastic
regime and the threshold strain for this reaction decreased with the oscillatory
frequency This didnrsquot appear for the other two POE systems and should be attributed
to the long chains branched (LCB) in it In transient shear flow the critical shear rates
for degradations of all POE were different from one another The rheological and
GPC results showed that as the shear rate increased the degradation was more and
more distinct and the duration to achieve one same level of molecular weight
decreased There is a kind of selectivity of shear rate on polymer chains for
degradation and the substantial cause is the relaxation time of polymer chains Higher
shear rate can enlarge the differences in mobility of the two parts with similar chain
length and increased the possibility of effective degradation in the middle of the
polymer chains or near the branching point
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
16
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Effect of Sorbitol Nucleator on Visco-Elasticity in Polypropylene --- Transient Shear Flow ---- Hideyuki UEMATSU Masataka SUGIMOTO Takashi TANIGUCHI Kiyohito KOYAMA Abstract We investigated the dynamic viscoelasticity and transient uniaxial elongational and shear flow of polypropylene (iPP) containing 05wt of 1324-bis-O-(p-methylbenzylidene)-D-sorbitol ( PDTS ) The PPPDTS exhibited a sol-gel transition with elevating temperature (T) in dynamic viscoelasticity measurement The critical temperature (Tc) and gel exponent n were 193(oC) and 23 respectively The gel exponent n is in agreement with predicted value by percolation theory From the results of start-up shear flow of PPPDTS stress overshoot is observed at 170oC (TltTc) within strain rates range From a viewpoint of stress overshoot we considered that maximum stress would be related a stability of network structure under shear deformation In the stress relaxation measurements at T=170oC in transient shear flow test mode the network structure was not broken at small strain region (γlt01) and longer relaxation curve than that of iPP was showed At large strain relaxation curves of PPPDTS asymptotically approached to those of iPP at larger strain region (01ltγlt20) This implies that the network structure is broken as increasing the step-strain In addition relaxation curves coincided with those of iPP at γgt20 From these results of transient shear flow test we will discuss the relationship viscoelasticity between rupture of network Key words PDTS Sol-gel transition transient flow break of network
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
17
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Investigation of polyethylene coupling reaction initiated by Dicumyl peroxide occurred in Haake internal mixer using two-dimensional numerical simulation
method Ji Zhou Wei Yu Chixing Zhou
Advanced Rheology Institute Shanghai Jiao Tong University Shanghai 200240 China
The coupling reaction of high density polyethylene initiated by Dicumyl peroxide in
complex high intensity flow fields of Haake internal mixer was analyzed with
simplified two-dimensional numerical simulation method The simultaneous
interactions between micromixing convection and successive evolution of system
viscosity were considered in our reaction model The effects of rotational speed and
evenuneven distribution of initiator on reactive procession were studied The
simulation results showed that the coupling reaction rate is accelerated with
increasing revolution speed due to the integral increase in strain rate and the case of
evenly distributed DCP had faster reaction rate than case of unevenly distributed It is
found that the advancement of reaction was not only affected by the value of
termination rate constant but also prominently affected by the local concentration of
secondary radicals The results indicated the mixing could significantly alter the
conversion and coupling product distribution
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
18
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Rotational Relaxation of T4-DNA in Aqueous Solution with Various Concentrations
Hiroki SATO1
Yuichi MASUBUCHI2
1 Department of Applied Chemistry Tokyo University of Agriculture and Technology
Tokyo 184-8588
2 Department of Applied Chemistry Tokyo University of Agriculture and Technology amp
JST-PRESTO Tokyo 184-8588
Abstract In this study individual molecular motion in concentrated DNA solutions is investigated as a
model system for universal polymer dynamics It has been reported that individual DNA motion can
be directly observed by fluorescent microscopy even in the concentrated solutions [1] Since the
observed dynamics of large DNA can be regarded as flexible string discussions based on the
theories for flexible and natural polymers [2] such like polystyrene have been performed and the
availability has been confirmed for dilute solutions However concentrated and entangled DNA
solutions have not been well investigated as model system of polymer in general We have reported
that concentration dependence of self-diffusion coefficient of T4-DNA solution is essentially the
same with polystyrene solution ranging from dilute to entangled concentrations [3] In this study to
extract conformational dynamics of DNA rotational relaxation was investigated
T4-DNA (166kbp 56μm NIPPON GENE) with various concentrations (0-600μMbp) in 05times TBE
buffer solution was used with a small amount of probe DNA labeled by YOYO-1 fluorescent dye
(Molecular Probes) From the observed images motion of the probed DNA were individually traced
and observed around for 5 min and gyration ellipse for the DNA image was extracted
Auto-correlation function of tilt angle of the ellipse was calculated and the relaxation time was
obtained The concentration dependence of the relaxation time shall be discussed with consistency of
the diffusion coefficient
[1] T T Perkins D E Smith S Chu Science vol264 819 (1994)
[2] M Doi and S F Edwards The Theory of Polymer Dynamics (Clarendon Oxford 1986)
[3] H Sato and Y Masubuchi ProcPOLYCHAR-14 219 (2006)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
19
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
A Novel Interfacial Synthesis of Hydrophilic Magnetite Nanoparticles
and their surface coating Ke Tao Kang Sun and Hongjing Dou
The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China
By using a novel interfacial coprecipitation method hydrophilic magnetite
nanoparticles capped with amine groups are facilely fabricated In the approach
di-n-propylamine and watercyclohexane mixture act as the alkali and medium
respectively so that the coprecipitate reaction is confined only to the interface
between water and cyclohexane It is confirmed by several kinds of characterizations
that the resultant nanoparticles possess not only relatively narrow size distribution but
also hydrophilic amine-decorated surface which provides them the capability of
being further modified by other molecules A systematic evaluation of the effects of
temperature solvents and amines were performed and the results showed that the size
and aggregation of nanoparticles can be tailored by adjusting the parameters The
mechanism of the nucleation and growth of nanoparticles during interfacial
coprecipitation is also discussed based on the results of characterizations Afterwards
the magnetite nanoparticles were coated with a silica layer by classical Stoumlber method
However this method deposited a thick layer of silica on the surface of magnetite
nanoparticles which would sharply decrease their magnetization Therefore we
replaced the ammonium solution in classical Stoumlber method by a basic amino acid
L-lysine to slow down the reaction rate As a result the thickness of silica coating on
periphery was controlled to be thinner than 20 nm and magnetization was successfully
kept The influence of silica coating layer on the interaction between nanoparticles
and solvents was expected to be evaluated by rheology method as well as the
magnetic dipolar interaction between individual nanoparticles
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
20
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Particle Tracking in a drying process
So Youn Kim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email milky83snuackr
Abstract
The main purpose of this study is to measure the diffusion coefficient in drying process with Particle Tracking Method versus time The drying is essential to industrial process as well as coating process In conjunction with industrial demand the focal point is to preserve its uniform distribution and control other phenomenon which is expected during drying process Therefore calculating the change of physical properties in coating film would be a great help to governing drying system and expecting the change of coating film such as polymer solution In this research we have focused on the diffusion coefficient as physical property of coating film
As a method of measuring the diffusion coefficient we selected the Multiple Particle Tracking(MPT) technique in that assumptions and limitations of microrheology also can be applied in solution during drying process like homogeneous physical property no-slip boundary conditions Brownian random force and negligible inertia Also we could neglect possible error factors such as thickness change and convection due to solvent evaporation with quenching the sample to keep evaporation and providing adequate experiment environment Ultimately this study provides basic information in relation with industrial coating and drying method
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
21
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Strong magnetic field-induced orientation and new phase formation in a low-molecular weight hydrogel
Yeonhwan Jeong Akifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Materials Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Shigeo Hara Shigeru Okamoto Katsuhiro Yamamoto (Nagoya Institute of Technology) Kazuo Sakurai (The University of Kitakyushu)
Shinichi Sakurai (Kyoto Institute of Technology)
When two transparent aqueous solutions of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa) were mixed an opaque gel phase was formed via carboxylate anion-Na cation-carboxylate anion interaction During gelation process strong magnetic fields were applied in two different manners (i) Static magnetic field (10 T) parallel to a capillary axis was applied (ii) A rotating magnetic field (10 T 15 rpm) perpendicular to the capillary axis was applied Note that the capillary contained the gelating solution The structure of aggregates thus formed was investigated with small-angle X-ray scattering (SAXS) In the absence of the strong magnetic field aggregates in a gel formed lamellar structure with a spacing of 46 nm (original phase) and the lamellar structure was not oriented But under a strong magnetic field lamellar structure was perpendicularly oriented against an applied rotating magnetic field
NNaO2C CO2Na
CO2NaNaO2C
CO2Na
O
GLD OleNa Fig 1 Chemical structures of tetrasodium NN-bis(carboxylatomethyl) glutamate (GLDA) and sodium oleate (OleNa)
876543210
68 wt static MF(original phase + new phase)
68 wt no MF(original phase D=46 nm)
q nm-1
Log[
I(q)
au
]
1
2
2
3
3 4
4
1 New phase D=40 nm
Fig 2 SAXS profiles for aqueous gels with 68 wt GLDA+OleNa in water Rotating MF means that the magnetic field is perpendicular to the capillary axis Static MF means that the magnetic field is parallel to the capillary axis
As shown in Fig 2 in the presence of the strong magnetic field coexistence of two kinds of lamellar structures with spacing of 46 nm and 40 nm (new phase) was observed The latter one is considered to be a bi-stable structure under the magnetic field by which the aggregation state of GLDA and OleNa might be affected
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
22
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Nonlinear Dynamics Bifurcation and Stability of Film Blowing Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The complicated nonlinear dynamics in film blowing process has been investigated
focusing on the multiplicity bifurcation and stability in the dynamic solutions of the
system using both theoretical model simulation and experiments A number of
interesting findings have been revealed about the dynamics of the process including a
fundamentally different behavior of the system with maximum three steady states for
the non-isothermal operations in contrast to the isothermal approximation where only
two steady states were predicted These differences have been identified as stemming
from the multiple values the air pressure inside the bubble can take on depending upon
the values of the bifurcation parameters of the system The stability of the three steady
states also displays many different patterns dictated by the process conditions
including the hysteresis in the bifurcation diagrams These stability results of the
system are quite reminiscent of those in the well-known CSTR (continuous stirred tank
reactor) cases found in the literature of chemical reaction engineering The theoretical
models of the film blowing system developed by this study produce quite accurate
predictions of the bubble and film shape results both in the steady state and the
transient solutions as compared with experiments It is considered that the findings of
this study can be utilized to readily enhance the stabilization and optimization of the
film blowing operation
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
23
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Measuring viscoelastic behavior of dilute suspensions with
particle tracking microrheology
Heekyoung Kang Yoonjae Yim Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1579 Email snowdrop0925navercom
Abstract
Many kinds of rheometers were developed to characterize the viscoelastic behavior of materials However due to their difficulty in applying to dilute suspensions several complementary techniques have been developed to measure viscoelastic properties of materials as such Especially particle tracking microrheology using Brownian motion of particles in a sample to get rheological properties has recently been improved both theoretically and experimentally Compared to other conventional rheometers this method has a lot of advantages such as small sample volume detecting spatial variation of local rheological properties and less damage to samples With these advantages microrheology is more suitable to measure the properties of complex materials such as dilute suspensions than other mechanical rheometries We measured viscoelastic properties of standard materials such as glycerol and PEO solution which provided good agreements with conventional rheometers Additionally we could characterize dilute silica suspensions with different pH which means different microstructures and polymer resins that are frequently used in dental treatments
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
24
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Stress development in suspension coating process
Sunhyung KimKyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email jazz7607snuackr
Abstract This study explores the stress development of suspension coating film in coating and
drying process During and after solidification of coating film the coating layer shrinks due to solvent evaporation Constrained shrinkage after solidification due to adhesion to a rigid substrate evokes the stress development [1] The stress in the coating layer results in defects such as peeling cracking curling and stretched pattern In order to accomplish defect-free coating with proper drying condition it is important to understand the evolution of stress development Therefore we developed the in-situ coating stress measurement apparatus using cantilever deflection method [2]
Some researchers have studied on stress evolution during suspension film formation [3 4] But little is known about the evolution during coating and drying process In this study we focused on how the stress which is developed during coating process of high shear rate has influenced on that of drying process The coating materials were characterized by rheological measurement and they complemented our stress measurement results to figure out the stress development of coating and drying process Reference [1] L F Francis A V McCormick D M Vaessen and J A Payne 2002 J Materials Science
37 4717 [2] J A Payne A V McCormick and L F Francis 1997 Rev Sci Instrum 68 4564-4568 [3] CJ Martinez and JA Lewis 2002 J Am Ceram Soc 85 2409-2416 [4] C Petersen C Heldmann D Johannsmann 1999 Langmuir 15 7745-7751
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
25
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Simple Model for the Uniform Coating Weights of Cr-free Coating Liquids in Steel Products
Hak Yul Kim1 Hyun Wook Jung1 and Du Hwan Jo2
1Dept of Chemical and Biological Eng Korea Univ Seoul Korea 2Surface Tech Res Group POSCO Research Laboratories Kwangyang Korea
Electorgalvanized steel sheets have been finally produced via roll coating processes of chromate andor Cr-free resin coating liquids on the zinc surface to enhance corrosion resistance and additional functional properties In the roll coating process for steel products the optimal control of coating weights on the substrate plays a key role in providing an excellent quality of the final products Therefore effects of resin coating liquids and roll coater conditions on the coating weights in the roll coating processes have been carried out in this study The roll coater operations include both forward and reverse modes with respect to strip direction Also the key factors affecting the coating weights such as theological properties of coating liquids stripapplicator roll speed ratio applicatorpick-up roll speed ratio and nip pressures between the rolls have been systematically examined Through the statistical DOE procedure using Minitab Statistical Program of experimental results a simple regression model which is easily applicable in the steel industry for optimal coating weights in the roll coating process has been developed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
26
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Studies on discrete patch coating process
Yoon Dong Jung Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-9125 Email efefintizencom
Abstract Patch coating is a coating method to make a rectangle patterns regularly on the
continuous passing web Recently it is mainly used for secondary lithium battery industry and flat panel display systems In spite of its large application field it is one of the undeveloped research fields
In this research an experimental study was carried out to investigate the effect of rheological properties in patch coating process We made coating solutions which have a similar shear viscosity but different elastic modulus and extensional property We found that the elastic modulus difference influences on suction length and pressure profile As lower elastic modulus solution is used the suction length increases and the pressure overshoot at supply patch valve decreases
In future work we will install the measuring sensor of in-situ wet coating thickness on present equipment and then expect to analyze the relation between pressure overshoot data and wet coating thickness profile at the start line on the patch
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
27
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Spontaneous Homeotropic Orientation of Nano-Cylinders Upon Morphological Transition from
Spherical Microdomains in Block Copolymer Films
HYoshida1 SSakurai1 KYamamoto2
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 JAPAN 2 Department of Materials Science Nagoya Institute of Technology Nagoya 466-8555 JAPAN
Block copolymers undergo microphase separation in several tens of nanometers because of strong segregation between constituent block chains comprising different chemical species Depending on composition the morphology of the microphase-separated structures can be altered from spheres cylinders or gyroid to lamellae It is well known that physical properties of block copolymers strongly depend on the morphology Not only the morphology but the orientation of microdomains are key factors to be taken into account in order to control materials properties more efficiently such as imparting anisotropy of properties To control orientation of microdomains is therefore one of the fundamental ways to novel specialty materilas Generally imposing a flow field works well to orient cylindrical microdomains such that the cylinders orient parallel to the flow To our best knowledge there is no report of perpendicular orientation of cylinders in a thick film (thickness in 01 ~ 10 mm range) Self-organization ability of block copolymer may be applied to this problem One of the promising strategies is a directional coalescence of spherical microdomains in the direction perpendicular to the sample film as shown in Figure 1 In this concept the resulted cylinders are therefore spontaneously oriented perpendicularly The sample used is an triblock copolymer (Mn = 66times
104 MwMn = 103 volume fraction of PS is 016 volume fraction of butylene moiety in PEB block chain is 041 PS polystyrene PEB polyethylenebutylene) A selective solvent n-heptane was used for the solution casting where n-heptane is good for PEB and poor for PS The thickness of the as-cast film was approximately 05 mm The as-cast film was subjected to heating at 2min from 700 to 2377 in a silicone-oil bath In this process two-dimensional small-angle X-ray scattering (2d-SAXS) time-resolved measurements were performed at BL45XU SPring-8 Figure 2 shows the edge view 2d-SAXS patterns for the SEBS sample cast from the n-heptane solution at various temperatures in the range from 700 to 2377
For 700 ~ 900 the 2d-SAXS pattern was elliptic When the sample heated up higher than the glass transition temperature of PS (100 ) the pattern transformed into a round shape which actually took place around 120 ~ 130 It was found however that the spherical morphology still remained ie spheres did not transform into cylinders yet The transition took place much more later as the temperature proceeded to the range of 215 ~ 230 Right after the transition it was found that the resultant cylinders already oriented perpendicularly as shown in Figure 2 Although at 2336 the orientation reached the best sudden homogenization occurred It is because the sample underwent order-to-disorder transition and therefore the oriented cylinders suffered from dissolution Based on this result we can discuss mechanism of spontaneous perpendicular orientation which cannot be included here due to limitation of space
Figure 2 Edge view 2d-SAXS patterns for SEBS at various temperatures in the range of 700 to 2361(n film normal)
Figure 1 Schematic representation of a directional coalescence of spherical microdomains
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
28
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Particle simulation in simple shear flow
Sungup Choi Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
TEL 82-2-880-1580 Email someman0snuackr
Abstract Particulate suspension simulations are performed in simple shear flow In this study
we used Brownian dynamics Stokesian dynamics and micro-macro simulation for particulate suspension Stokesian dynamics and micro-macro simulation method take hydrodynamic interaction between the flow and particles into account while Brownian dynamics does not Additionally micro-macro simulation gives us the information of the disturbed flow field We will compare the simulation results and characterize the particulate suspension in simple shear flow by rheological properties Comparing rheological properties of particulate suspension in various volume fraction and shear rate we are going to see hydrodynamic interaction effect
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
29
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Linear and Nonlinear Viscoelastic Behavior of Poly (Dimethyl Siloxane) Gels Hideaki TAKAHASHIab Yoshitaka ISHIMUROa and Hiroshi WATANABEb
a Toray Research Center Inc Sonoyama Otsu Shiga 520-8567Japan
b Institute for Chemical Research Kyoto University Uji Kyoto 611-0011Japan
Abstract Linear and nonlinear viscoelastic behavior was investigated for a poly (dimethyl siloxane)
(PDMS) gel formed though a bulk double-liquid crosslinking reaction of two types of vinyl-terminated PDMS prepolymers of the molecular weights Mpre cong 35 times103
Time-temperature superposition worked for the linear viscoelastic storage and loss moduli Grsquo and Grdquo and master curves at 20˚C were constructed in a wide range of angular frequency ω (= 103-10-5 s-1) by combining the data obtained from dynamic oscillatory tests and creep tests With decreasing ω to 10-1 s-1 Grdquo decreased in proportion to ω 06 and Grsquo rapidly decreased to its equilibrium plateau at the modulus Ge = 2800 Pa On a further decrease of ω well in the plateau regime of Grsquo Grdquo decreased in proportion to ω 03 Thus the gel exhibited the fast and slow relaxation processes characterized with these types of power-law behavior of Grdquo The molecular weight between the crosslinks evaluated from the Ge data (as well as the equilibrium swelling ratio in toluene) Mc cong 340 times103 was about ten times larger than Mpre The crosslinking reaction was made in the bulk state but still gave such a scarce gel network (with Mc cong 10 Mpre) possibly because a large amount of sol chains and dangling chains had diluted the trapped entanglements during the reaction From the analysis of the Grsquo and Grdquo data on the basis of the above Mc value and the intrinsic Rouse relaxation time the fast relaxation process was assigned as the Rouse-like constraint release (CR) process of individual gel strands The polydispersity of the strands was found to be essential for the power-law behavior (Gpropωn with n cong 06) to be observed in the plateau regime of Grsquo The slow relaxation process was related to fluctuation of the crosslinking points which is equivalent to cooperative Rouse-CR motion of many gel strands connected at these points
The values of strain at the onset of nonlinear behavior and rupture were obtained from stress relaxation measurements For small strains γ the stress decays with time but only to the equilibrium plateau value of Geγ indicating the linear response of the gel However for γ gt 2 the stress decayed more significantly (below Geγ) and the nonlinearityrupture was observed This behavior suggested that shorter network strands in the gel were largely stretched and progressively broken at smaller strain to exhibit the nonlinearity and rupture On the basis of these results the heterogeneity of the gel strand length was discussed
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
30
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Finite element analysis of elastic solidStokes flow interaction
problem
Jinsuk Myung Wook Ryol Hwang Kyung Hyun Ahn Seung Jong Lee
School of Chemical and Biological Engineering Seoul National University Seoul Korea
School of Mechanical amp Aerospace Engineering Gyeongsang National University Jinju Korea
TEL 82-2-880-1580 Email cocoa98snuackr
Abstract The distributed Lagrangian multiplierfictitious domain (DLMFD) method is one of
the ways to solve solidfluid interaction problems We apply the DLMFD formulation of Yu [J Comput Phys 207(2005) 1] for the flexible bodyfluid interactions to simulate the elastic solidStokes flow interaction problem which is based on the formulation of Glowinski et al [Int J Multiphase Flow 25 (1999) 755] This work is done to find out proper condition of solidfluid interaction problem that we will use later on We choose a simple system a bottom-attached bar in pressure driven pipe flow so we can easily compare the results by changing sets and conditions below Four different sets were used in the same system by changing two factors One is Lagrangian multipliers distribution and the other is solidfluid interaction condition In four sets we checked mesh refinement with changing conditions such as solidfluid mesh ratio pseudo-time step scale etc We found the effect of each factor and optimum conditions This result is used to extend our study to suspended elastic particle systems in the Stokes flow
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
31
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Direct numerical simulation of mold filling process with (elliptic) particle
filled fluids Shin Hyun Kang Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We present a direct method for the two-dimensional mold-filling simulation of fluids filled with a
number of circular disk-like rigid particles It is direct simulation method such that the hydrodynamic
interaction between particle and fluid is fully considered We employ a volume-of-fluid(VOF) method for
the evolution of the flow front and the DLM-like fictitious domain method for the implicit treatment of
the hydrodynamic interaction Both methods allow the use of the fixed mesh ofr the entire computation
The discontinuous Galerkin method has been used to solve the concentration evolution equation and the
rigid-ring description has been introduced for the treatment of force-free torque-free particles The gate
region of the finite area subject to uniform velocity profile has been introduced to add up a number of
discrete particles continuously into the computational domain
In the future we will present to develop elliptic particle shape instead of rigid circular particles
Unlikely to the circular particle case obtaining the uniform distribution of points on the elliptic particle
boundary is not obvious The uniformity of points considered here means the equi-distance distribution of
points with respect to the arclength We will attempt randomly distributed and oriented many elliptic
particles in the mold filling process and plot the evolution of the particle orientation of the elliptic particle
problem
This work has been supported by the 2nd stage of BK21 project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
32
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Capillary spreading of drops of particulate suspensions on the solid
substrate
Hyun Jun Jung Wook Ryol Hwang
School of Mechanical and Aerospace Engineering Gyeongsang National University Gajwadong 900
Jinju 660-701 South Korea
We developed a finite-element technique for studying capillary spreading of droplets on the solid
surface that contains solid particles We focus in this work only on 2D and especially on spontaneous
spreading by the capillary force We consider the problem just after a droplet of particulate suspensions
hits a solid surface Since small droplets about tens of microns in diameter and low spreading rates
typically a few mmsec are considered typical values of We Re and Bo are negligible Based on the
standard velocity-pressure formulation of the finite element method we have the following distinctive
feature in our numerical technique (i) Interface capturing by the level-set method and re-initialization
using line segments along the interface (ii) the solution of the evolution equation for the interface by the
discontinuous Galerkin (DG) method (iii) the distributed Lagrangian multipliers (DLM) method with the
combined weak formulation for implicit treatment of rigid particles and (iv) the third-order accurate and
stable time-stepping method (TVD-RK3) We examine the particle effects on the capillary spreading of a
droplet Our numerical scheme seems to be good to capture the steady equilibrium contact angle The
result show the equilibrium contact angle was 60 degree We have successfully demonstrated the particle
motion in a spreading drop by the capillary force by a specific example and discussed effects of particles
on the droplet spreading on a solid substrate
This work has been supported by the NURI project
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
33
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Nonlinear Dynamics and Stability of 2-D Viscoelastic Film Casting Process
Dong Myeong Shin Joo Sung Lee Hyun Wook Jung and Jae Chun Hyun
Department of Chemical and Biological Engineering Applied Rheology Center
Korea University Seoul Korea
The various aspects of the nonlinear dynamics and stability of non-isothermal film
casting process have been investigated solving a 2-dimensional viscoelastic simulation
model equipped with the Phan Thien-Tanner (PTT) constitutive equation by employing
a finite element method (FEM) This study represents an extension of the earlier report
(Kim et al J of Non-Newtonian Fluid Mech 2005) in that two important points are
additionally addressed here on the subject the non-isothermal nature of the film
casting and the differentiation of extension-thickening (strain hardening) and
extension-thinning (strain softening) fluids in their different behavior in the film casting
process The PTT model known for its robustness in portraying dynamics in the
extensional deformation processes which include the film casting of this study along
with film blowing and fiber spinning as well renders the transient and steady-state
solutions of the dynamics in the 2-D viscoelastic non-isothermal film casting capable
of explaining the effects of various process and material parameters of the system on
the film dynamics of the process Especially the different behavior displayed by two
polymer groups ie the extension-thickening LDPE type and the extension-thinning
HDPE type in the film casting can be readily explained by the PTT equation - included
simulation model The three nonlinear phenomena commonly observed in film casting
ie draw resonance oscillation edge bead and neck-in have been successfully
delineated in this study using the simulation and experimental results
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
34
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Flow Instabilities in ForwardReverse Roll Coating Processes
Sang Kwon Han Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun Department of Chemical and Biological Engineering
Applied Rheology Center Korea University Seoul Korea
Roll coating as a post-metered coating process is distinguished by the use of one or more gaps between rotating rolls to meter and apply a liquid to web or substrate Two basic types of roll coaters are characterized by the relative direction of roll surface motion in the gap ie in forward roll coating the roll surfaces move in the same direction and in reverse roll coating they move in opposite directions
In this study dynamics and flow instabilities in forward and reverse roll coatings have been experimentally investigated using both Newtonian and viscoelastic liquids Incorporating flow visualization equipment coating thickness and position of meniscus at the film splitting region have been examined in forward roll coating and the metered coating thickness and dynamic contact line have been measured in reverse roll coating Also by observing flow instabilities of Newtonian and viscoelastic liquids occurring in these flow systems various coating windows have been established
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
35
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Optimal Die InternalExternal Designs for Patch Slot Coating
Seo Hoon Shim Dong Myeong Shin Hyun Wook Jung and Jae Chun Hyun
Dept of Chemical and Biological Eng Applied Rheology Center Korea University Seoul Korea
Flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process which is widely used in manufacturing IT products such as the secondary batteries has been investigated for the purpose of optimal process designs As a matter of fact the flow control in patch mode coating systems is more difficult than in continuous case because of its transient or time-dependent nature The internal die and die lip designs for uniform coating products have been obtained by controlling flow patterns of coating liquids issuing from slot die Numerical simulations have been carried out using Fluent and Flow-3D packages Flow behavior and pressure distribution inside the slot die have been compared with various die internal shapes and geometries In the coating bead region efforts to reduce irregular coating defects in head and tail parts of one coating patch have been tried by changing die lip shapes It has been concluded that optimal die internal design has been developed guaranteeing uniform velocity distribution of both Newtonian and non-Newtonian fluids at the die exit And also optimal die lip design has been established providing the longer uniform coating layer thickness within one coating unit
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
36
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Dynamics of DNA tumbling in shear to rotational mixed flow
Jeong Yong Lee Joo Sung Lee Hyun Wook Jung Jae Chun Hyun and Susan J Muller
Department of Chemical and Biological Engineering Applied Rheology Center Korea University Seoul Korea
Department of Chemical Engineering University of California at Berkeley CA USA
Recent developments in direct visualization methods coupled with Brownian dynamics simulations have allowed the dynamics of single DNA molecules in flow to be studied with unprecedented detail These studies have shed light on the dynamics of long chain molecules relevant to a spectrum of applications from the manipulation of single DNA molecules in lab-on-a-chip applications to the processing of synthetic polymers in complex industrial flows To date these single molecule studies have focused primarily on pure shear flow and on extensional flow Shaqfeh and Chu and co-workers have investigated DNA tumbling dynamics in pure shear flow and near shear flows In this study we investigated the tumbling dynamics of single DNA molecules across the spectrum of flow type from pure shear to pure rotational flows over a wide range of flow strength Wi by using Brownian dynamics simulations In shear tumbling pathways and periods agree well with earlier studies and experiments In rotation-dominated flows a new tumbling pathway is identified Based on these results we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow type parameter for transition from the shear-like flow regime to the rotation-dominated one
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
37
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Diffusion of Individual DNA Molecules in Concentrated DNAPEG Blend Solutions
Hiroshi KAWAKITA1
Yuichi MASUBUCHI2
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and
Technology Tokyo 184-8588Japan
2 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract Polymer blends have been widely investigated due to their importance in industry and polymer
science Though there have been large number of studies for equilibrium thermodynamics and phase
separation kinetics [1][2] dynamics of polymers in blends has not been clarified yet It has been
known that isolated polymer shows the coil-globule transition [3] depending on the condition of
surrounding medium If the polymer concentration increase macroscopic phase separation may
occur However overall picture bridging between the phase transition in macroscopic range and the
coil-globule transition in molecular level has not been proposed In this study we use DNAPEG
aqueous solutions as model system of polymer blends taking the advantage of fluorescent
microscopy where individual DNA motion and phase structure can be observed at the same time
PEG solution was mixed with Salmon sperm DNA stained by DAPI and prove DNA (T4-DNA)
stained by YOYO-1 for the solution TBE buffer suppressing the changes of DNA and
2-mercaptoethanol as antioxidant The final concentrations were as follows Salmon sperm DNA
from 010 to 10 mMbp DAPI at 010 for DNA concentration T4-DNA at 10 nMbp YOYO-1 at
20 for DNA concentration TBE at 50 (vv) 2-ME at 30 (vv) PEG from 30 to 90
M(monomer unit) It was found that separation of DNAPEG occurs for DNA concentrations beyond
10 mMbp after annealing for 3 days We shall discuss diffusion and conformational dynamics of
prove DNA under the phase separation
[1] F S Bates Science 251 4996 (1991)
[2] H M Lee O O Park J Rheol 38 5 (1994)
[3] K Minagawa Y Matsuzawa K Yoshikawa A R Khokhlov M Doi Biopolymers 34 555
(1994)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
38
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Simulations of Entangled Polymer Dynamics in Temperature Controlled Melt Spinning of Poly (ethylene terephthalate)
Hitoshi HOTCHI1
Yuichi MASUBUCHI2 Kensuke NAKAHARA3 Takeshi KIKUTANI4
1 Tokyo University of Agriculture and Technology Tokyo 184-8588 Japan
2 Tokyo University of Agriculture and Technology amp JST-PRESTO Tokyo
184-8588 Japan
3 Japan Chemical Innovation Institute Tokyo 145-0062 Japan
4 Tokyo Institute of Technology Tokyo 152-8552 Japan
Abstract The purpose of this study is to analyze the effect of temperature and flow rate distributions
along the spin line on polymer dynamics In melt spinning process of high molecular weight poly
(ethylene terephthalate) (PET) mechanical properties of as-spun fiber are affected by entangled
polymer dynamics in the spin line Conventional simulations of melt spinning are inadequate to
grasp the polymer dynamics because of using constitutive equations based on phenomenological
models[1] In this study polymer dynamics is simulated by combinations of continuum and
molecular level simulations By the continuum level simulation a tentative steady-state flow field
and temperature distribution are obtained by a set of equations for conservation of mass energy and
momentum with Newtonian flow assumption For the obtained flow rate and temperature the
coarse-grained molecular simulation[2] is performed and entangled polymer dynamics are calculated
The effect of the temperature and flow rate distributions on the polymer dynamics shall be discussed
[1] S Kase and T Matsuo J Polym Sci PartA 3 2541 (1965)
[2] Y Masubuchi et al J Chem Phys 115 4387 (2001)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
39
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Rheology of semi-dilute solution of Ecoli DNA
Taro KINOSHITA1 Shihori Sohya 2 Yutaka Kuroda2 Yuichi Masubuchi3
1 Department of Organic and Polymer Materials Chemistry Tokyo university of Agriculture and Technology
Tokyo 184-8588Japan
2 Department of Biotechnology and Life sciences Tokyo university of Agriculture and Technology Tokyo
184-8588Japan
3 Department of Organic and Polymer Materials Chemistry Tokyo university of
Agriculture and Technology JST-PRESTO Tokyo 184-8588Japan
Abstract The purpose of this study is to determine rheological parameter of DNA solutions It has been reported that long
chain double-stranded DNA can be directly observed by fluorescent microscopy and shows similar behavior to the
universal polymer models such as the Zimm model and reptaion model The polymer dynamics has been
discussed by macroscopic rheological data it gives an important insight to rheology through rheological
parameters such a plateau modulus relaxation time etc if rheology and molecular motion of DNA can be
obtained and compared Mason et al measured dynamic modulus of calf-thymus DNA for dilute and semi-dilute
conditions [1] However so far entangled DNA solution has not get been examined In this study rheological
measurement of DNA solutions extracted from Escherichia coli (Ecoli) with various DNA concentrations up to
entanglement condition was performed Ecoli BL21 (DE3) was incubated overnight at 37 The cell suspension
contained approximately 69times1010 cells DNA was extracted from Ecoli through cell lysis RNA treatment and
protein precipitation The molecular weight of the obtained DNA has narrow distribution at 100kbps according to
steady field gel electrophoresis measurement DNA is dispersed in aqueous buffer containing Tris-HCl and EDTA
with concentration of 10μMbp~300μMbp across the overlapping concentration for the obtained DNA (724μ
Mbp) Dynamic viscoelastic measurement is performed by a rotational rheometer equipped with cone plates with
25 and 50mm in diameter Transition in between different dynamical modes and parameters shall be discussed
[1] TGMason ADhople DWirtz Macromolecules31 3600(1998)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
40
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Flow Analysis of Liquid Silk in the Spinneret of Bmori silkworm
Motoaki MORIYA 1 Yuichi MASUBUCHI12 Kosuke OHGO3 Tetsuo ASAKURA3
1Department of Organic and Polymer Materials Chemistry Tokyo University of Agriculture and
Technology Koganei Tokyo 184-8588 Japan
2 JST-PRESTO Koganei Tokyo 184-8588 Japan
3Department of Biotechnology Tokyo University of Agriculture and Technology Koganei
Tokyo 184-8588 Japan
Abstract The purpose of this study is clarification on fiber formation process of liquid silk
It is known that silk fibroin is stored as an aqueous solution in the silk gland [1] When liquid silk is
subjected to shear at the spinneret in silkworm the intramolecular hydrogen bonding is transformed
to an intermolecular one which leads to fiber formation [1][2] However the mechanism of fiber
formation in Bmori silkworm is still not fully elucidated
In this study flow calculation using finite element method was performed to obtain the information
of local shear rate in the spinneret of silkworm In this calculation both a 3D model of the spinneret
and the shear viscosity of liquid silk were needed Firstly the structure of the spinneret was created
by using 3D reconstruction method from sequential sectional images obtained by optical
micrographs[2] Secondly the shear rate dependence of shear viscosity of liquid silk extracted from
the silk gland [3] was measured by a rotational rheometer In the measurement decreasing viscosity
was observed below a critical shear rate and the viscosity increased above the critical shear rate with
the fibrillation of liquid silk On the simulation boundary condition is regulated by the flux or
pressure and the slip on the canal wall is neglected From the result of the simulation we shall
discuss the initation site of the fibrillation in the spinneret consider the motion of muscles and find
out the intimate mechanism of silkwormsrsquo fiber formation
[1]KS Hossain et al Biomacromolecules 4 2 (2003)
[2]Yamane et al Macromolecules3618 (2003)
[3]TAsakura et al Biomacromolecules in press (2006)
[4]AOchi et al Biomacromolecules 3 6 (2002)
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
41
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Magnetic Orientation of Microdomains in Block Copolymers degAkifumi Yasui (Kyoto Institute of Technology)
Fumiko Kimura (National Institute for Material Science) Tsunehisa Kimura (Tokyo Metropolitan University)
Jeong Yeonhwan Shinichi Sakurai (Kyoto Institute of Technology) E-mail sanga006kitacjp
Abstract
Magnetic orientation of microdomain structures has been examined for block copolymers consisting of non-crystalline block chains Microdomains are considered to be orientated by applying the magnetic field bearing in mind that microdomain interface possesses a diamagnetic susceptibility However it has not been clearly comfirmed yet In order to enhance the magnetic effect doping of a methal chelate compound selectively to the microdomain was carried out We used a triblock copolymer polystyrene-block-poly(ethylene-co-but-1-ene)-block-polystyrene (SEBS) which forms PS cylinders in PEB
matrix The dichloromethane solution of SEBS sample containing a metal chelate compound was cast on aluminum foil in the presence of high magnetic field of 12T The sample was further annealed at 190 for 3 h in the absence of the magnetic field and then the orientation of PS cylinders was examined with small angle X-ray scattering (SAXS) at room temperature It was found that lamellar microdomains are oriented parallel to the magnetic field After annealing the oriented lamellae in the absence of the magnetic field 6-folded pattern appeared indicating that a well-ordered hexagonal cylinders were formed
Fig1 Stability of cylindrical microdomain in the presence of the high magnetic field Arrows denote lines of magnetic force
3
2
1
0
x10
4
360
(b) n
q=02nm-1
(a)
B n
q=02nm-1
30024018012060
(b)
(a)
inte
nsity
(a
u)
0azimuthal angle μ degree
Fig2 2d-SAXS patterns of edge views for (a) as-cast film (in the presence of the high magnetic field B) and (b) annealed film (in the absence of B)
Fig3 Variation of scattering intensity of the first-order peak as a function of the azimuthal angle μ
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
42
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Microphase-Separated Structure and Molecular mobility of shorter end-block chain in Asymmetric Poly(methyl acrylate)-block- polystyrene-block-poly(methyl acrylate) Triblock Copolymer
J Fukuhara1 K Yamamoto2 S Shimada2 S Sakurai1
1 Department of Polymer Science amp Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan 2 Department of Materials Science amp Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Asymmetric triblock copolymers poly(methyl acrylate)-block-polystyrene block-poly(methyl acrylate) (M1-S-M2) have different molecular weights of both end-block chains Matsen theoretically have shown that the morphological behaviors for asymmetric triblock copolymers and for symmetric triblock copolymers are different It is considered that this behavior is ascribed to dissolution of the shorter end-block chains (M2) into the PS phase In this study we investigated morphology and molecular mobility of the shorter end-block chain (M2) of asymmetric triblock copolymers by small-angle X-ray scattering (SAXS) temperature-modulated differential scanning calorimetry (MDSC) and electron spin resonance (ESR) Conducting atom transfer radical polymerization (ATRP) we synthesized various asymmetric triblock copolymers as shown in Table1 From SAXS experiments MSM15 forms a cylinderical structure while other samples form lamellae From results of both DSC and ESR experiments (Figs1 and 2) we confirmed that only MSM15 showed lower Tg of PS and lower mobility of M2 (shorter) chain This gives clear evidence of the dissolution of the M2 chains into the PS phase which gives rise to the morphological alteration from lamella to cylinder
Table 1 Characteristics of Asymmetric M1-S-M2 Triblock Copolymers
Endo
120100806040200Temperature ()
87
96
96
96
18
18
18
100
10
18
MSM15
MSM20
MSM45
MSM36PMA homo
PS homo20x10-9
18
16
14
12
10
08
τ c (s
ec)
600050004000300020001000Mn of M2
443K
463K
453K
Fig 2 Average relaxation time of M1-S-M2
triblock copolymers M2 chains were labeled with nitroxide radicals
Fig 1 MDSC themograms of various triblock copolymers and respective homopolymers
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
43
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
High Frequency Dielectric Relaxation Behavior of Aqueous Solutions ofPoly(vinyl sulfate) Salts with Various Counterions
Osaka University Y Satokawaand T Shikata
1 IntroductionAqueous solutions of polyelectrolytes exhibit
the dielectric relaxations assigned to rotation ofion-pairs formed by counterion condensation anddetachment of water molecules hydrated to thepolymer chains in a frequency range above 100MHz In this study we investigated high fre-quency dielectric relaxation behavior of aqueoussolutions of poly(vinyl sulfate) salts with a strongelectrolyte groups sulfates directly bonded to themain chain and various counterion species suchas Na+K+ and (CH3)4
+ (TMA+)
2 ExperimentalAqueous solutions of poly(vinyl sulfate) salts
with three different counterions XPVSs (X+ =Na+K+ and TMA+) were prepared Concentra-tions of sample solutionscP were ranged over 1to 200 mM in monomer unit
Dielectric relaxation measurements were car-ried out over the angular frequency (ω) rangefrom 63times 106 to 13times 1011 radsminus1 at 25
The real and imaginary parts of the relativeelectric permittivity of the solute polyelectrolytes∆ϵrsquo and∆ϵrdquo were calculated by eq (1)
∆ϵprime = ϵprime minus Φϵprimew ∆ϵrdquo = ϵrdquo minusκdc
ϵ0ωminus Φϵwrdquo (1)
whereϵrsquo and ϵrdquo are the real and imaginary partsof sample solutionϵwrsquo and ϵwrdquo are those of bulkwaterΦ represents the fractional contribution ofbulk waterκdc is the dc conductivity due to thepresence of dissociated ionic species andϵ0 is thepermittivity of a vacuum respectively
The number of tightly hydrated watermolecules per monomer unit of XPVSm wasevaluated from the concentration dependence ofΦ assuming eq (2)
Φ =1minus ϕ
1+12ϕ
minus 18times 10minus6mcP (2)
where ϕ is the volume fraction of solutemolecules
3 Results and DiscussionThe dependence of∆ϵrsquo and∆ϵrdquo on ω for aque-
ous solutions of XPVSs atcP = 75 mM are shownin Fig 1 as typical examples
Two relaxation modes in a frequency rangelower than 109radsminus1 were attributed to the fluc-tuation of counterion distribution vertical to thepolymer chain axis and the rotational relaxation
of ion-pairsτ3 and τ2 modes respectively ac-cording to the previous studies1
A relaxation mode in a higher frequency rangeseemed to be attributed to the detachment of wa-ter molecules hydrated to the hydrophilic sul-fate groups Therersquore no significant differencesamong the dielectric spectra for aqueous solu-tions of XPVSs with different counterions bearinghydration numberm dependent on X+ speciesHowever the fact that them values obtained (Ta-ble 1) are perfectly identical with the hydrationnumbers of X+s (Na+ 6 K+ 3 sim 4 and TMA+
0) revealed that sulfate groups scarcely kepttightly hydrated water molecules Consequentlywe concluded that the relaxation mode found atτ1 = 7times109radsminus1 was attributed to another mech-anism such as the rotation of dipolar sidechainsnamely sulfate groups
The dielectric relaxation behavior of aqueoussolutions of dodecylsulfate salts also sustainedthat sulfate groups dielectrically keep no tightlyhydrated water molecules
References
(1) Nakamura K Shikata TMacromolecules200639 1577
Table 1 Numbers of tightly hydrated watermoleculesm per monomer unit of XPVS (X+ =Na+K+ and TMA +)
X Na+ K+ TMA+
m 6 3 0
10-2
10-1
100
101
102
103
107
108
109
1010
1011
∆ε o
r ∆ε
ω rads-1
τ1
-1τ3
-1 τ2
-1
Na+
K+
TMA+
∆ε ∆ε
Fig 1 Dependence of∆ϵrsquo ∆ϵrdquo on ω forXPVS (X+ = Na+K+ and TMA+) in aqueous solu-tions atcP = 75 mM Solid lines represent the best fitcurves obtained by the summation of three Debye-typerelaxation modes with relaxation timesτ1 τ2 andτ3
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
44
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Effects of Hydrogen-Bonds on the Dynamics of Benzyl Alcohol
SNobukawa OUrakawa and TShikataDepartment of Macromolecular Science Graduate School of Science Osaka University
1 IntroductionSeveral alcohols in the liquid state exhibit
clear dielectric relaxation process due to the largedipole moment of hydroxyl groups It is alsoknown that this relaxation process is strongly af-fected by the formation of inter-molecular hy-drogen bonds (H-bonds) between hydroxyl (OH)groups Schwetdtfer et al studied dielectric relax-ation behavior of the mixtures consisting of mono-hydric alcohols (ROH) and n-alkanes and exam-ined the relationship between the H-bonding struc-ture and the dynamics of ROH They concludedthat alcohol molecules formed chain-like hydrogenbonded clusters in which two types of moleculesin terms of the H-bonded structure existed iesingly-hydrogen bonded ROH (either O or H atomin the OH group is not H-bonded by anotherOH) and doubly-hydrogen bonded ROH (both Oand H are H-bonded by another OH groups) andthese two types of ROH molecules had different re-laxation times (the former has shorter relaxationtime)
We have been studying the effects of H-bonding on the dynamics of polymeric systemswhere hydroxyl groups are partially incorporatedaiming at controlling the properties of the poly-mer materials In this study we investigated thedielectric relaxation behavior of a low mass com-pound benzyl alcohol (BzOH C6H5CH2OH) inthe mixture with toluene (Tol) as the model sys-tem of partially hydroxymethylated polystyrene
2 ExperimentThe complex dielectric constant was mea-
sured as a function of frequency ω in the range of628times106 - 126times1011 rad sminus1 at temperatures be-tween 5 C and 40 C Infrared absorption spectraof the BzOHTol mixtures was measured in therange of wave number 400 - 7000 cmminus1 at roomtemperature
3 Result and DiscussionFigure 1 shows the IR spectra corresponding
to the OH bond stretching vibration The broadpeak from 3200 to 3500cmminus1 and the relativelysharp peak around 3550cmminus1 were attributed tothe stretching vibrations of the H-bonded OHgroups and the free (non-H-bonded) ones respec-tively It can be seen that the relative intensity ofthe H-bonded OH becomes smaller with decreas-ing the BzOH concentration xBzOH
The complex dielectric constant εlowast(ω) of
BzOHTol mixtures could be well represented bythe sum of two Debye functions (eq1)
εlowast(ω) = εinfin +sum
j=12
∆εj
1 + iωτj(1)
where εinfin is the high frequency dielectric constantτ is the relaxation time and ∆ε is the dielectricintensity From the ∆ε of the two modes the frac-tion of mode 1 (slow mode) ∆ε1(∆ε1 + ∆ε2)was determined This fraction was found to bean increasing function of xBzOH Figure 2 showsxBzOH dependence of the two relaxation times τ1
and τ2 The τ1 decreases with decreasing xBzOHwhile τ2 is almost independent of xBzOH Thesefeatures are qualitatively the same with those ofROHn-alkane mixtures reported by Schwedtfegeret al Therefore by following their interpretationwe can assign the observed two dielectric relax-ation modes 1 and 2 (slow and first modes) forBzOHTol system to the rotational motion of thedoubly and singly H-bonded BzOH respectivelyFrom the quantitative comparison of the εlowast(ω)data between BzOHTol and ROHn-alkanes wefound that the H-bonding cluster size of BzOH wassmaller than that of ROH
χBzOH
10090703
Fig 1 Infrared spectra for BzOHTolmixture xBzOH indicates mole fraction ofthe benzyl alcohol These absorbance dataare normalized by the peak values of aro-matic C-H bond
xBzOH
ττ ττ
ττ ττ
ps
Fig 2 Dependence of τ1andτ2 on xBzOHfor BzOHTol mixture
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
45
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
High Frequency Dielectric Relaxation Behavior of Aqueous Solution of Poly(Sulfobetaine)s
Yousuke Ono and Toshiyuki Shikata
Department of Macromolecular Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan
yonochemsciosaka-uacjp Poly[3-dimethyl (methacryloyloxyethyl)-ammoniumpropanesulfonate] PDMAPS one
of the poly(sulfobetaine)s bears zwitterionic group consisting of an ammonium cation and sulfonic anion isolated by propyl group in monomer units (Figure 1) One of characteristic properties of PDMAPS in aqueous solution is their low solubility In a solution of PDMAPS with Mw = 11times105 liquid-liquid two phases co-exist at 25˚C in a concentration range from 01 to 1M in monomer units The reason for this low solubility may be the formation of intra- andor intermolecular associations via dipole-dipole interactions between zwitterionic groups which result in densely cross-linked networks of polymers leading to segregation
In this study high frequency dielectric relaxation behavior was examined for PDMAPS aqueous solutions as a function of angular frequency(ω) from 628 times 106 to 126 times 1011 rad s-1 with varying concentration cp molecular weight Mw and temperature T Since zwitterionic groups of PDMAPS have intrinsic permanent electric dipole moments obvious dielectric relaxation was observed for aqueous solution of PDMAPS due to the rotational motion of the zwitterionic groups
The fastest relaxation mode observed at τDH ~ 015 ns was attributed to the dehydration or exchange of water molecules tightly bound to PDMAPS Rotational relaxation mode of zwitterionic groups of PDMAPS was found as a broad loss peaks described by the summation of two Debye type relaxation functions with the relaxation times of 2 ns and 10 ns as shown in Figure 2
The magnitude of the relaxation strength owing to the rotation of zwitterionic groups in phase separated PDMAPS solutions was slightly smaller than that of an aqueous solution of DMAPS monomers which is molecularly soluble in aqueous solution (Figure 3) This findings suggest that the some zwitterionic groups dipoles of PDMAPS in a polymer rich phase in two-phase solutions are slightly aligned in an anti-parallel manner to reduce the total dipole moment
Fig2 Dependence of ∆εrsquo and ∆εrdquo on ω for PDMAPS water system at 25˚C
01
1
10
100
106 107 108 109 1010 1011
∆ε
∆ε
ω rad s-1
1000mM
500
200
100
τDH-1
τ2-1
τ1-1
H2C C
CH3
C
O
O
(CH2)2
N CH3H3C
(CH2)3
SO3
n
Fig1 PDMAPS
0
10
20
30
40
50
60
0 200 400 600 800 1000
∆ε1+∆
ε 2 or
∆εm
cp or cm mM
PDMAPS Mw=11times105 ∆ε1+∆ε
2
SPE monomer ∆εm
Fig3 Dependence of ∆ε1+∆ε2 and ∆εm on the concentrations of PDMAPS cp and DMAPS cm at 25˚C
DMAPS
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
46
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Polymer conformation under fast flow
Tatsuya Iwamoto
Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Entangled polymers under fast flow have been expected to take anisotropically
deformed conformation In this study we investigated the polymer conformation
under steady shear flow in condensed polymer solutions with small-angle neutron
scattering (SANS) By using solutions of block copolymers which consist of
protonated polybutadiene (hPB) and deuterated polybutadiene (dPB) blocks
dissolved in a deuterated oligo-butadiene (oBd) we were able to observe the
conformational changes of different parts of the polymer chain with the shear rate
The samples used were hPB-dPB diblock (hPBM w =178times10 3 dPB M w =960times10 3 )
and two dPB-hPB-dPB triblock (type-A hPB M w =276times10 3 dPB M w =237times10 3
hPB M w =931 times 10 3 type-B hPB M w =535 times 10 3 dPB M w =200 times 10 3 hPB
M w =478times10 3 ) copolymers all having nearly the same length of the dPB block and
oBd (M w =186times10 3 ) The concentration of block copolymer was 28wt We used a
Couette cell to impose the steady shear flow Comparing the results of diblock
sample and triblock samples (especially of type-B) we noted that the degree of chain
orientation of the latter was higher than that of the former This result suggests that
the differences of the degree of the chain orientation are consistent with the
differences of polymer chain dynamics However the differences of the degree of the
chain orientation appeared to be less significant compared to those expected from the
current tube model
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
47
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48
Dynamics of Poly(lactic acid) in carbon dioxide at high pressure
Tomohito Iwashige Yumi Matsumiya Tadashi Inoue Hiroshi Watanabe
Institute for Chemical Research Kyoto University
Abstract
Dielectric measurement was conducted for poly(lactic acid) (PLA) in carbon dioxide (CO2) at high
pressures CO2 is dissolved in PLA more with increasing pressure and this dissolution is expected
to affect the chain dynamics The PLA chains have both type-A dipoles parallel along their
backbone and type-B dipoles perpendicular to their backbone Therefore two dielectric relaxation
processes reflecting the global motion of the chains (normal mode) and local segmental motion
(segmental mode) are expected to be observed The loss peak due to the segmental mode
relaxation was observed at 1 kHz at around 345 K However the loss peak due to the normal mode
relaxation was not observed because of the ionic conduction Thus this time we report the
dielectric segmental mode relaxation of PLA in CO2 at high pressure The dispersion curve shifted
toward higher frequency and the dielectric intensity decreased slightly with increasing CO2 pressure
In analogy with the conventional time-temperature superposition we attempted the ldquotimendashCO2
pressure superpositionrdquo we made the lateral and vertical shift of each curve to the reference curve in
vacuo (PCO2 =0 MPa) It was found that the dispersion curve became broader slightly with
increasing CO2 pressure meaning that the time-CO2 pressure superposition does not work perfectly
The vertical shift factor (intensity shift factor) for this superposition gave the CO2 concentration in
PLA Dynamics of PLA plasticized by CO2 at high pressure was found to be similar to that of PLA
plasticized in usual solvents
The Second International Workshopfor Far East Asian Young Rheologists
January 26-28 2007Kyoto Institute of Technology JAPAN
48