High-Frequency Organic Thin-Film Transistors on Flexible ...

The 5th International Conference on Advanced Electromaterials Nov 5-8, 2019 | Jeju, Korea

10-0142

High-Frequency Organic Thin-Film Transistors on Flexible Substrates

Hagen Klauk*

Max Planck Institute for Solid State Research, Germany

Organic thin-film transistors (TFTs) can typically be fabricated at temperatures below 150 °C and thus not only on

glass, but also on unconventional substrates, such as plastics, paper and textiles, which makes them potentially

useful for flexible, large-area electronics applications, such as rollable or foldable displays and sensors. In some of

the more advanced applications envisioned for organic TFTs, such as the integrated row and column drivers of

flexible active-matrix displays, the TFTs have to be able to control electrical signals of a few volts at frequencies of

several megahertz. Given the relatively small charge-carrier mobilities in organic TFTs, this implies the need for very

small channel lengths. To meet this requirement, we have developed a high-resolution stencil lithography process

that allows organic TFTs with channel lengths as small as about 1 µm to be fabricated on flexible plastic substrates.

These TFTs have transit frequencies greater than 1 MHz and ring-oscillator delays below 200 ns at supply voltages of

about 3 V.

*Corresponding author Hagen Klauk

Affiliation Max Planck Institute for Solid State Research

E-mail address

[email protected]


10-0536

Mechanical Performance Effect By Capacitance Of Ionic Electroactive Polymer Actuators With Various Dielectric Materials

Joohee Kim1, Minjeong Park1, Seonpil Kim2, Minhyon Jeon1*

1Inje University, Korea

2Gyeongju University, Korea

Ionic electroactive polymer (IEAP) actuators have received interest because of their advantageous properties

including their large displacement, high energy density, light weight, and low power consumption under a low

electric field. However, they have a low blocking force under driving, and it is difficult to control the thickness of the

ionic polymer membrane. Materials with high dielectric constant such as oxide (e.g. SiO2, TiO2) and polymer (e.g.

polyethylene) will increase the capacitance and will affect the driving property of the IEAP having the capacitor

structure. Therefore, various materials with various dielectric constants are added in the ionic polymer membrane to

compare and increase the driving property. In this study, IEAP actuators were fabricated using Nafion composite

membrane with various additives having each other dielectric constant. A heat press two-step process is also

developed to produce a constant and uniform membrane. The fabricated Nafion membrane with 0.2 wt% multi-

walled carbon nanotubes have the largest displacement and highest blocking force. As a result, the developed heat

press two-step method can be used in various polymer-casting fields, and the fabricated carbon nanotube-based

IEAP actuators can serve as useful references in fields such as flexible robotics and artificial muscles.

*Corresponding author Minhyon Jeon

Affiliation Inje University

E-mail address

[email protected]


10-0550

Solution-processed Silicon Oxide Charge Trap Layer for Memory Thin-film Transistors

Sang-Hoon Lee, Amos Amoako Boampong, Jae-Hyeok Cho, Kyeong Min Yu, Jae-Hyun Lee, Min-Hoi Kim*

Hanbat National University, Korea

Solution-based process is a potential method for substituting all or part of conventional processes due to its low-cost

compatibility and has been actively conducted in various fields including sensor, circuits, and memory devices [1].

The memory is a core component of most electronic devices and the possibility of applying solution process in its

manufacturing brings large economic profit. Charge trap memory (CTM) is a nonvolatile memory transistor which is

operated by controlling the number of trapped charges in the charge trapping layer. The CTM transistor is a basic

circuital element for highly integrated memory such as NAND flash since the writing voltage of the CTM transistor is

larger than the pass voltage [2, 3]. However, there has not been much research on charge trap memory using

solution process.

In this work, we fabricated organic charge trap memory transistor using a spin-coated silicon oxide layer as a charge

trapping layer. The charge trap memory using silicon oxide layer showed good memory window and rewritable

characteristic by applying appropriate gate bias voltage. This approach will provide a technological basis for solution-

processed memory circuits.

[1] Christos D. Dimitrakopoulos and Patrick RL Malenfant, Adv.Mater., 14, 99 (2002).

[2] K.-J. Baeg, D. Kihm, J. Kim, B.-D. Yang, M. Kang, S.-W. Jung, I.-K. You, D.-Y. Kim, &Y.-Y. Noh, Adv. Funct. Mater. 22,

2915 (2012)

[3] B. Eitan, U.S. Patent No 5,768,192, (1998)

*Corresponding author Min-Hoi Kim

Affiliation Hanbat National University

E-mail address

[email protected]


10-0556

Wearable, transparent smart contact lens sensors for wireless glaucoma diagnostics

Joohee Kim1, 2, Minjae Ku1, 2, Eun Kyung Cha1, 2, Jihun Park1, 2, Young-Geun Park1, 2, Hyeon Seok An1, 2, Jang-

Ung Park1, 2*

1Yonsei University, Korea

2Center for Nanomedicine, Institute for Basic Science (IBS), Yonsei University, Korea

Eyes can provide rich physiological information, and they offer extensive diagnostic potential as a sensing site,

making the use of contact lens sensors viable for non-invasive monitoring of many diseases and conditions. However,

previously reported smart contact lenses could not be produced on soft contact lenses due to their opaque and

brittle components and materials. In addition, the bulky equipment that was required to supply power to the circuits

in the contact lens sensor or to receive the signals from the sensors on the contact lens could limit the users’

movements. Thus, we demonstrated a human pilot trial of transparent, soft, smart contact lens that can monitor the

intraocular pressure via a smartphone. This contact lens sensor reads the intraocular pressure by amplifying a small

strain because the mechanical deformations can be concentrated on the designed soft region of the hybrid

substrates composed of materials with different Young’s modulus. In addition, the electronic circuits for wireless

communication are integrated fully by stretchable packaging methods, making a smartphone the only equipment

that is needed. The resulting soft, smart contact lens provides real-time, wireless operation, and a human pilot trial

was conducted to monitor the intraocular pressure. The value of continuous monitored intraocular pressure is

expressed quantitatively on the smartphone. The human pilot experiment of the smart contact lens demonstrates

the immense potential to be used as a diagnostic tool for healthcare monitoring.

*Corresponding author Jang-Ung Park

Affiliation Yonsei University

E-mail address

[email protected]


10-0624

Three-dimensional carbon nanostructure/copper nanowire and Nafion composite membrane based ionic polymer metal composite actuator+

Seongjun Park1, Minjeong Park1, Mindong Kim1, Seonpil Kim2, Minhyon Jeon1*

1Inje University, Korea

2Gyeongju University, Korea

One of the electroactive polymer, Ionic polymer metal composite (IPMC) has been studied as an actuator in the

biomedical, artificial muscle, and medical fields because of its advantages of lightweight and flexibility as well as

large bending deformation under low driving voltage. In previous studies, there were several attempts to increase

electrical and mechanical properties of IPMC. The studies about adding various materials in an ionic polymer

membrane were many reported. Especially, the metal nanowire and carbon based materials as additives significantly

increased ion conductivity properties in IPMC. The copper nanowire (Cu NW) among the metal nanowire materials

has low cost, good thermal and electrical conductivity, and flexibility. The carbon based materials such as carbon

nanotube (CNT) and graphene had good mechanical strength, excellent electrical conductivity, and gas-

impermeability. In this study, we fabricated three-dimensional carbon structure (3DCS)/Cu NW and Nafion

composite membrane based IPMC actuator. The 3DCS/Cu NW is synthesized through hydrothermal method and low

temperature chemical vapor deposition growth, which was synthesized like powder. The 3DCS/Cu NW was dispersed

in Nafion membrane and fabricated the IPMC actuators based on 3DCS/Cu NW-Nafion composite membrane. The

electrical and mechanical properties of 3DCS/Cu NW based IPMC has been investigated by using cyclic voltammetry

and driving test analyzer.

* Correspondence to : [email protected]

+. This research was supported by a grant to Bio-Mimetic Robot Research Center Funded by Defense Acquisition

Program Administration, and by Agency for Defense Development (UD160027ID)

*Corresponding author Minhyon Jeon

Affiliation Inje University

E-mail address

[email protected]


10-0664

High-Resolution, Reconfigurable 3D Printing of Liquid Metals for Integrated Soft Electronics

Young-Geun Park, Sang Beom Bak, Hyeon Seok An, Jang-Ung Park*

Yonsei University, Korea

Increasing device density in electronic circuits has required an exponential growth of complex three-dimensional

conductive paths. Recently, as the form factors of electronic devices have been expanded toward soft and

deformable characteristics, there is a desperate need for a technology capable of forming a three-dimensional

structure of stretchable conductors with high resolution, high aspect ratios and minimized displacement errors.

Among various stretchable conductors, liquid metals are widely regarded as a conductor for stretchable electronics

due to their superior stretchability and self-healability with high conductivity. However, liquid metals are not

examined for its use in providing three-dimensional structures with high resolutions (< 10 μm) for stretchable and

reconfigurable integrated circuits. Herein, we present the high-resolution printing of liquid metals and its direct

reconfiguration into three-dimensional structures. Liquid metals were printed with a minimum line width of 1.9 μm

using fine-diameter nozzles, and then reconfigured into three-dimensional shapes by controlling the kinetic adhesion

with substrates. During reconfiguration, the diameter of the three-dimensional line was not significantly changed

from the pristine line width. Furthermore, the thin native oxide on the surface formed by reconfiguration showed

the effect of retarding the penetration of liquid metals through contacted metals, with no great influence on the

contact properties compared to oxide-free surface. This three-dimensional reconfiguration technology of high-

resolution liquid metal structures was demonstrated as various applications in electronics such as three-dimensional

antenna with tunable resonance frequency, switchable electrodes in light emitting diode (LED) pixels, and three-

dimensional interconnections for micro-LED arrays, providing potentials for achieving higher integrity in the

integrated soft electronics.



E-mail address

[email protected]


10-0860

Flexible CNT Web Film for Curved Heating Elements under Extreme Temperature Conditions

Ji-Hwan Ha1, Hyeonjun Song1, Hyun-Woo Kim1, Dongearn Kim2, Youngjin Jung1*, Sung-Hoon Park1*

1Soongsil University, Korea

2Korea Instituted of Industrial Technology, Korea

Under extreme temperature conditions, heating elements are needed a rapid heating property and long-term cycle

stability. Carbon nanotube (CNT) based films can be used as ideal heating units owing to its superior electrical and

thermal properties. However, CNT polymer composites are not appropriate in extreme conditions such as very low

temperature (-50 ℃) and high temperature (300 ℃) due to the poor thermal stability of the polymer matrix. In this

study, we fabricated the CNT web film as heating elements consisting of pure CNTs through the direct spinning

method. The CNT web film showed flexibility at extremely low temperature (-196 ℃), while fracture occurred in

case of CNT polymer composite. We conducted the electrical heating experiments of curved CNT web film to

observe the heating uniformity and flexibility. The CNT web film showed rapid heating properties (from 26 ℃ to

240 ℃, in 5 sec) and uniform heat distribution (temperature departure less than 5 %) without thermal aggregation.

*Corresponding author 1 Youngjin Jung

Affiliation Soongsil University

E-mail address

[email protected]

*Corresponding author 2 Sung-Hoon Park


E-mail address

[email protected]


10-1098

Haze-Free Transparent Electrodes Using Metal Nanofibers with Carbon Black Shells for High-Temperature Stability

Sangyoon Ji, Gon Guk Kim, Jihun Park, Jang-Ung Park*


The key metrics for rapidly-emerging, transparent optoelectronic devices are to achieve more conductive and

thermally-stable transparent electrodes (TCEs) that at minimal costs. Herein, we demonstrate the simple and cost-

effective coaxial electrospinning process that facilitates ultra-long and continuous copper nanofibers (CuNFs)

conformal covered with a carbon black (CB) shell. The coaxial electrospinning enabled electrospinning of metal inks

directly on the target substrates; therefore an additional deposition process or photolithography were not required.

The resulting CuNF networks exhibit outstanding optoelectronic performance. By adding black materials to the

polymer shell solution, the reflection of light from the metal surface was suppressed from 4% to -1% and, therefore,

the high-clarity of the CuNF electrodes was achieved. Furthermore, a single CuNF showed 2.5 times superior

electromigration-robustness compared to that of a single silver NF. This property is essential for high-performance

electronic devices. Utilizing the outstanding electromigration-robustness of CuNFs, a highly transparent heater was

demonstrated by Joule heating; the temperature of the heater exceeded 800 ℃. Furthermore, the lifetime of the

heater could be improved by utilizing the self-healing effect of the heater under AC bias.



E-mail address

[email protected]


10-1122

Human-Interactive, Active-Matrix Displays with Direct Visualization of Tactile Pressures for Wearable Electronics

Jiuk Jang, Byungkook Oh, Jang-Ung Park*


Human-interactive displays involve the interfacing of a stimuli-responsive sensor with a human-readable response.

Vision is considered to be the most intuitive and informative human stimulus so that the visualization of electrical,

thermal, and mechanical data is important for various applications. To exploit interactive displays for the

visualization of tactile pressure, active-matrix addressing using arrays of field-effect transistors (FETs) is

indispensable since it is advantageous for minimizing the number of wiring with less signal crosstalk, thereby

providing better spatial resolution and contrast and facile integration with electric circuit.

Here, we demonstrate the fabrication of a human-interactive display in which active-matrix arrays of pressure-

sensitive transistors with local air patterns are fully integrated with pixels of organic light-emitting diodes (OLEDs). In

this active-matrix array, a single transistor can act as a pressure sensor solely due to the elastomeric partition wall

which supporting the air-gap dielectric layer between the gate electrode and channel. For the visualization of the

pressure, the intensity of light emitted from individual OLED pixels is tuned where the surface is touched, and also

can quantify the magnitude of the applied tactile pressure with wide detectable pressure range from 180 Pa to ~3

MPa. Furthermore, these transistors can be three-dimensionally integrated with dual-side emissive OLED pixels.

Here local pressing increases the light intensity of these pixels and then the underlaid channel can absorb this light

successively to generate additional photocurrents from the pressure-sensitive transistors for amplifying their

sensitivity by a factor of nine further. This human-interactive display can visualize tactile pressure directly, suggesting

its substantial promise for various application fields, such as soft robotics and intelligent human-machine interfacing.



E-mail address

[email protected]


10-1350

2.5D printing of wireless power transfer module and its application to operating electrochromic device on non-flat surfaces

RAJARAM KAVETI, Murali Bissannagari, Jihoon Kim*

Kongju National University, Korea

Direct ink writing on three-dimensional (3D) or curved surfaces is a newly emerging challenge in printed electronics

due to the difficulties in developing suitable inks and fabrication methods for highly curved surfaces. So far, very few

efforts have been made to realize devices over a curved surface. Fabrication of optimized direct printing inks is

highly significant for the production of high-quality printing on curved surfaces. The effect of solid, solvent, and

dispersant on the printability and ink rheological properties such as viscosity, storage modulus, yield stress,

thixotropy and viscoelasticity of various inks were tuned and investigated by rheological tests under steady and

dynamic shear conditions. Here, for the first time, we demonstrate the direct printing of Electro Chromic devices

(ECD), wireless power transfer (WPT) modules and ceramic layers directly onto the highly curved surfaces

(hemispherical glass substrates with radius of curvature ~ 50) with viscoelastic conductive, ceramic, and magnetic

inks designed for the highly curved surface printing. WPT module consists of an inductor coil (Ag), and capacitors

(Ag/BaTi2O3/Ag) are used to realize a parallel resonant LCR circuit. Furthermore, a soft ferrite layer (NiZn-Ferrite)

direct printed on inductor coil, these soft ferrite layer in WPT module plays important roles in (a) enhancing

magnetic coupling between the inductor coils transmitting and receiving the magnetic field, and (b) preventing the

magnetic field from reaching any conductive object, electronic devices, or human bodies near the WPT module.

Laser annealing using an IR laser with various laser fluences was applied to enhance the magnetic property of the

soft ferrite layer printed on the highly curved surface. The performance of the printed WPT module on a highly

curved surface was demonstrated by transmitting wireless power to ECD through the magnetic resonant coupling.

This work may find potential applications, including wearable electronics, optoelectronics, biomedical devices,

sensors, and 3D-Hybrid electronics.

Keywords: Direct Ink Writing, Highly Curved Surface, Rheology, Viscoelastic Ink, Thixotropy, NiZn-Ferrite,

Hemispherical Surface, Electro Chromic Devices, Wireless power transfer.

References: 1) Adams, JA Lewis, et al. 2011. “Conformal Printing of Electrically Small Antennas on Three-Dimensional

Surfaces.” Advanced Materials 23 1335-1340.

*Corresponding author Jihoon Kim

Affiliation Kongju National University

E-mail address

[email protected]


10-1546

Anisotropically aligned Ni embedded composite for high resolution pressure sensor array application

Hanul Kim, Seongdae Choi, Yongtaek Hong*

Seoul National University, Korea

Recently, as the interest in electronic skin (e-skin) has been increasing, a lot of research has been done about flexible

and wearable physical sensing platforms. The electronic skin is supposed to be morphologically similar to the real

human skin and send electrical signals in response to the various external stimuli. For the e-skin to mimic the real

skin, pressure sensing does an important role to get a variety of physical information and requires high flexibility and

sensitivity with high resolution. In many previous studies, complex structures have been reported, but they have the

disadvantages of high cost and low resolution.1,2

In this research, we fabricated flexible pressure sensor array based on Nickel (Ni)-polymer composite of which Ni

particles are anisotropically aligned with external magnetic field. With the strong magnetic field, Ni, the

ferromagnetically conductive particles, are vertically aligned in the uncured polymer, and conduction paths are

formed. Since the conduction paths are formed anisotropically and each is isolated horizontally, crosstalk between

neighboring pixels, which were implemented by printed electrodes array, can be minimized.3 This composite is also

suitable for making sensor array of different resolutions by simply printing electrodes at the top and bottom of it,

which is useful for e-skins that require tens of dpi. Using the sensor array, pressure mapping over 100 dpi resolution

could be performed as shown in Fig. 1. The sensing device was fabricated by the following procedure: First, the Ni

particle and polymer were mixed using mechanical stirrer, the mixture was poured into mold and degassed. After

that, magnets were located at the top and bottom of the mixture, and the sample was annealed. Fig. 2 plots the

electrical characteristic of the pressure sensor according to the applied external pressure. The sensitivity and the

reliability of the sensor depend on several factors such as concentration, morphology of the fillers, the thickness of

the composite, and the kind of polymers. Considering these conditions, sensor array with high sensitivity and

reliability was optimized.

Using this vertical alignment with strong magnetic field, we can make large area pressure sensor array that can be

fabricated under easy fabrication process.

References

1. He Tian et al, “A Graphene-Based Resistive Pressure Sensor with Record-High Sensitivity in a Wide Pressure

Range”, Nature Scientific Reports 5, 8603 (2015).

2. C. Pang et al. “A flexible and highly sensitive strain-gauge sensor using reversible interlocking of nanofibres”,

Nature Materials 11, p. 795–801 (2012).

3. S. Kim et al. “Negatively Strain‐Dependent Electrical Resistance of Magnetically Arranged Nickel Composites:

Application to Highly Stretchable Electrodes and Stretchable Lighting Devices”, Advanced Materials 26, p. 3094-3099

(2014).

*Corresponding author Yongtaek Hong

Affiliation Seoul National University

E-mail address

[email protected]


10-2423

Piezoelectric Device of MWCNT-PVDF Composite with PEDOT:PSS Electrode treated by Ethylene Glycol

Young-Taek Lim1, Paik-Kyun Shin2*

1Electric Power Research Institute, Korea

2Inha University, Korea

Piezoelectric device of MWCNT-PVDF composite was fabricated, where a spray-deposited PEDOT:PSS of enhance

electric conductivity was used as electrode. The PEDOT:PSS layer was immersed in an aqueous solution of ethylene

glycol to improve electric conductivity. Piezoelectric output characteristic was comparatively examined on devices

having PEDOT:PSS-electrode with/without ethylene glycol treatment. The device of PEDOT:PSS treated by ethylene

glycol showed higher output voltage and current characteristics than those of the device of pristine PEDOT:PSS.

*Corresponding author Paik-Kyun Shin

Affiliation Inha University

E-mail address

[email protected]


10-2446

Flexible organic non-volatile memory device with plasma polymerized styrene as memory layer

Boong-Loo Lee1, Hee-Sung Kim2, Paik-Kyun Shin3*

1Namseoul University, Korea

2Hee Sung Industry Co., Ltd., Korea

3Inha University, Korea

A floating-gate type organic memory was designed and fabricated aiming for a flexible non-volatile memory. A

completely dry process-setup was applied to the fabrication processes for floating-gate type organic memory device.

Thin film of plasma polymerized styrene was used as a memory layer. The flexible organic memory device prepared

on a PET substrate revealed a memory window of 6 [V] and retention time of over 2 [h].

*Corresponding author Paik-Kyun Shin

Affiliation Inha University

E-mail address

[email protected]


10-2872

Compliant Characteristics of Carbon Nanotube Electrodes for Electromechanical Applications

Seung Youl Kang*, Jaehyun Moon, Seong-Deok Ahn

Electronics and Telecommunications Research Institute, Korea

In this work, we investigated the carbon nanotube (CNT) films as a compliant electrode for actuating dielectric

elastomers. CNT films were fabricated by using a filtration-transfer process. Electromechanical actuating was

observed not to take place at the CNT mats themselves but at the interface between the CNT mats. From the

microscopic investigation, we can find out that structural compactness in CNT film is detrimental in achieving

electromechanical actuating. Optimized electromechanical performances were obtained in electrodes with modest

CNT aerial density (30 mg/m2) and open voids. To be specific, maximum strain of 17 % and transmittance of 86 %

were achieved. Our results suggest that in utilizing 1-D materials as electrode in transparent electromechanical

actuating, it important not only to maintain the electrical percolation but also provide relaxed electrode structure.

Our approach can be applied to basic components of optoelectronics devices, transparent tactile touch panels, and

so on.

*Corresponding author Seung Youl Kang

Affiliation Electronics and Telecommunications Research Institute

E-mail address

[email protected]


10-3051

Large area CNT web film for electric heating applications

Hyunwoo Kim, Sunghoon Park*, Youngjin Jung, Jihwan Ha, Hyeonjun Song

Soongsil University, Korea

We have demonstrated uniform rapid heaters based on large area carbon nanotube (CNT) web films consisting pure

CNTs through the direct spinning method. We conducted an electric heating test on the CNT web film synthesized

with large area. Aluminum panel can be rapidly heated from room temperature to 320 °c within 9 s incorporated

with CNT web film (applying a DC voltage of 20V). Its rapid heating profile analyses show that the performance of the

CNT web film heater is superior to that of conventional heater based on CNT/PDMS composite under the same

power consumption condition. Along with rapid heating performance, the CNT web film can be reached high heating

temperature up to 400 °c while CNT/PDMS composites have a low maximum temperature (~200 °c) due to the

limitations of polymer properties. In addition, the flexibility of the CNT web film further allows its facile application

to a curved substrate.

*Corresponding author Sunghoon Park


E-mail address

[email protected]


10-3249

Materials Engineered-1D and 2D Materials: Highly Stable Soft Electromaterials/Transparent Electrodes Toward Green Energy and

Environmental Applications

Yu-Lun Chueh*

National Tsing-Hua University, Taiwan

Low dimensional nanomaterials have attracted much attention due to their unique fundamental properties and their

potential applications in nanodevices. Nanoscale materials, compared to their bulk dimensions, can possess superior

electrical, optical, and mechanical properties, resulting in excellent mechanical toughness, high luminescence

efficiency, enhancement of thermoelectric property and low lasing threshold voltage. In my talk, I will deliver an

overall review on growth of 1D and 2D materials in my group as the soft electromaterials and its applications on

energy storage, energy harvesting and environmental application.

*Corresponding author Yu-Lun Chueh

Affiliation National Tsing-Hua University

E-mail address

[email protected]


10-3583

The Effect of Electrospinning Parameters and Comonomer Content on Poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] (PHBHx) Nanofibers

Reva Street1, Joanne Norris1, D. Bruce Chase1, Isao Noda1, 2, John Rabolt1*

1University of Delaware, USA

2Danimer Scientific, USA

Abstract:

Electrospun nanofibers of poly(3-hydroxybutyrate) (PHB) have previously been demonstrated to exhibit a d33

piezoelectricity of approximately 2-3 pC/N *1,2+. This effect is suggested to be due to the metastable planar zigzag β-

form. While PHB is a biocompatible and biodegradable polyester it is also highly crystalline and thus brittle with poor

processing characteristics. To improve material properties, random copolymers of PHB and PHAs with medium-

length sidechains have been a recent focus of our research. The medium-length side chains are excluded from the

PHB crystal lattice, which results in defects that affect the overall crystallinity of the polymer. Notably poly(3-

hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHx) has been found to affect the amount of crystallinity in a way that

is directly dependent on the comonomer ratio.

Recently we demonstrated that electrospun 3.9 mol% PHBHx also exhibits β-form when electrospun under specific

circumstances [3]. The nanofiber collection technique in particular has shown to be important, with a high-speed

rotating collector showing the highest level of β-form production. To expand on this discovery, comonomer content

and electrospinning parameters have been further explored to determine the extent of their effects. Nanofibers

were prepared in halogenated solvent solutions and electrospun onto flat, air-gap and rotating disk collectors. The

nanofiber morphology was assessed using scanning electron microscopy (SEM), while the extent of β-crystal

formation was determined by Fourier-transform infrared (FTIR) spectroscopy and two-dimensional wide-angle X-ray

scattering (WAXS). The degree of β-crystal formed was found to depend on the electrospinning collection technique

as well as the comonomer ratio. Although we have recently shown that 3.9 mol% PHBHx is also piezoelectric, the

exact effect of comonomer concentration on piezoelectric response as a function of crystal structure and

morphology is unknown but will be discussed.

References:

1. Cai, Z., Xiong, P., He, S., & Zhu, C. (2019). Improved piezoelectric performances of highly orientated poly (β-

hydroxybutyrate) electrospun nanofiber membrane scaffold blended with multiwalled carbon nanotubes. Materials

Letters, 240, 213-216.

2. Zviagin, A. S., Chernozem, R. V., Surmeneva, M. A., Pyeon, M., Frank, M., Ludwig, T., ... & Surmenev, R. A. (2019).

Enhanced piezoelectric response of hybrid biodegradable 3D poly (3-hydroxybutyrate) scaffolds coated with

hydrothermally deposited ZnO for biomedical applications. European Polymer Journal, 117, 272-279.

3. Gong, L., Chase, D. B., Noda, I., Liu, J., Martin, D. C., Ni, C., & Rabolt, J. F. (2015). Discovery of β-form crystal

structure in electrospun poly [(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate](PHBHx) nanofibers: from fiber

mats to single fibers. Macromolecules, 48(17), 6197-6205.

*Corresponding author John Rabolt

Affiliation University of Delaware

E-mail address [email protected]


10-3681

Soft electronics based on designer smart electromaterials and devices

Pooi See Lee*

Nanyang Technological University, Singapore

Self-powered electronics and autonomous systems are driving the next industrial revolution, particularly in human-

machine interface, wearables and robotic systems. The concepts of designer smart electromaterials and devices for

building electronics and energy devices are the key contributing factors for the connection between physical motion,

power generation and electronics operation. Developing conformable cutaneous electronics or deformable wearable

electronics operated in close proximity to human body will require robust and optimum electronic and mechanical

properties of soft, compliant, flexible and stretchable materials.

Our efforts focus on the incorporation of functional nanomaterials in soft matrices for tuning the electrical

conduction, opto-physical properties, charge transport and physico-chemical-mechanical properties. We designed

and prepared flexible transparent conductor using metallic nanowires and nanocellulose using a nanotechtonic

assembly network. This resultant micromesh provided an effective percolative pathways for electrons transport,

leading to high transparency and conductivity. Stretchable conductor was realized using liquid metal particles in

various elastomers. Liquid metal particles facilitated continuous electrical conduction under extreme stretching

strains, making them suitable for deformable electrodes in strain sensors and energy harvestors. Functional

nanomaterials such as black phosphorus nanosheets were adopted as charge trapping layer in enhancing

triboelectric charges for sensing and energy harvesting. Future prospects on contemporary and emerging

interdisciplinary designer materials and devices will be discussed.

*Corresponding author Pooi See Lee

Affiliation Nanyang Technological University

E-mail address

[email protected]


10-3706

Transient Electronics

Suk-Won HWANG*

Korea University, Korea

An ultimate goal of a conventional silicon-based integrated system is its capability to last forever without any

malfunction and physical deformation, in almost any practical uses. Recent works demonstrate a new class of silicon

electronics that has the opposite behavior -- it physically dissolves or disappears in water, environment or biofluids,

in a controlled fashion, at predefined times or on demand and with programmed rates. For example, (1) a complete

collection of transient electronic building blocks, including n- and p-channel silicon nanomembrane (NM) metal oxide

field effect transistors (MOSFETs), and their integration into circuits that disappear or functionally transform, (2)

sensors of light, temperature and strain, each of which uses functional materials and formats common to those for

the electronics, (3) photovoltaic and inductive devices for power supply, (4) experimentally validated, analytical

models of transience, suitable as design tools for engineered behaviours and (5) integrated examples in wirelessly

controlled, bio-resorbable devices that provide thermal therapy in an implantable form. This ‘transient’ technology

opens up completely new application opportunities for electronic devices in areas, such as implantable medical

devices that exist for medically useful timeframes but then dissolve and disappear completely by resorption into the

body. Use scenarios range from integration with living hosts (human/animal/insect/plant; on-dwelling or in-dwelling)

to indoor/outdoor environments such as buildings, roadways or materiel. Enabled devices include medical monitors

that fully resorb when implanted into the human body (“bio-resorbable”) to avoid adverse long-term effects, or

environmental monitors that dissolve when exposed to water ("eco-resorbable") to eliminate the need for collection

and recovery. Other concepts involve circuits that incorporate strategic regions with timed transience, to affect

controlled transformation in function. This talk summarizes recent work on ‘transient’ technology, ranging from

fundamental chemistry of the key materials, to development of various components and systems for biosensors, to

in vivo toxicity tests for biocompatibility.

*Corresponding author Suk-Won HWANG

Affiliation Korea University

E-mail address

[email protected]

The 5th International Conference on Advanced Electromaterials Nov 5-8, 2019 | Jeju, Korea 10-3769

Unconventional Bio-integrated Electronics towards Human-Machine Interface (HMI) Applications

Ki Jun Yu*


Many bio-integrated electronics used clinically must maintain high levels of performance

over extended periods of time. Longevity was especially challenging at the biotic interface, since the total device

thickness is restrained to achieve low bending stiffness, and the space for device

encapsulation is narrow. To address this grand challenge, I have developed a class of flexible active sensing matrix

with a capacitively coupled sensing strategy. The whole device is covered with an ultra-thin thermally-grown SiO2

layer, serving both as the dielectric for capacitively coupled sensing, and as the barrier for device encapsulation.

Experiments from accelerated testing suggest the potential for operation for many years while fully implanted. I

have successfully applied this system into two areas: i) monitoring micro-electrocorticographic (μECoG) activity on

the brain of none-human primate, and ii) mapping epicardial physiology on Langendorff-perfused rabbit heart model.

*Corresponding author Ki Jun Yu


E-mail address

[email protected]


10-3797

Miniaturized, Battery-free Wearable Sensors with Near-Field Communication Capabilities for Biomedical Application

Jeonghyun Kim*

Kwangwoon University, Korea

An ultrathin, lightweight, and flexible, near-field communication (NFC) device in a compact form is introduced, and a

systematic investigation of mechanisms, radio frequency characteristics and materials aspects related to optimized

structures are presented. This system provides mechanical strength, placement flexibility, and interfaces stress

minimization compared to other NFC technologies and wearable electronics. These concepts can be applied to many

different types of wireless communication systems, including biosensors and electronic implants.

Here, we present optical metrology approaches, optoelectronic designs, and wireless modes of operation that serve

as the basis for miniature, low-cost, and battery-free devices for quantitative information on blood oxygenation and

precise dosimetry at multiple wavelengths. These platforms use a system on a chip with near-field communication

functionality, a radio frequency antenna, photodiodes, resistors, and capacitors to exploit a continuous accumulation

mechanism for measurement. Versatile applications of this platform provide means for consumers and medical

providers to get helpful information about their blood health and modulate light exposure across the

electromagnetic spectrum in a way that can both reduce risks.

*Corresponding author Jeonghyun Kim

Affiliation Kwangwoon University

E-mail address

[email protected]


10-3935

Omnipresent Sensor Platforms

Wooyoung Shim*


Biomimetic structures represent an effective way to realize highly efficient materials or devices with unprecedented

properties. This strategy, however, suffers from intrinsic trade-offs with costly and complex conventional fabrication

processes, which make it difficult to widely adopt such technology for academic and industrial purposes. Here, I

present a conceptually different approach—using ubiquitous materials—whereby inartificially engineered design in

materials can mimic bio-inspired microstructures and substantially outperform other counterparts produced by

costly microfabrication processes. which is a step toward the realization of omnipresent electronics.

*Corresponding author Wooyoung Shim


E-mail address

[email protected]


10-3978

Characteristics of Liquid Metal under an AC Electric Field

Myunghwan Byun1*, Jong-Kyun Choi2 1Keimyung University, Korea

2Daegu-Gyeongbuk Medical Innovation Foundation, Korea

We have evaluated the steering and locomotion of a liquid metal (LM) under an AC electric field. The LM is a

compound of Ga and In that has good conductivity, low toxicity, and high surface tension. As a solute, the LM

maintains a water drop shape, especially in NaOH solution. In this paper, trapping and steering LM using an AC

electric field in NaOH solution are proposed. The dynamic characteristics of the LM can be attributed to frequency

variations in the vibration, micro-vibration, and cut-off frequency. These characteristics suggest that the LM may be

used for drug targeting and delivery. Within the cut-off frequency, an LM droplet could be trapped and steered

under an AC field, along an S-shaped path. The steering method proposed in this study can be applied for control

over soft robots, microdevices, micropumps, and drug delivery.

*Corresponding author Myunghwan Byun

Affiliation Keimyung University

E-mail address

[email protected]

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