Observations of Self Assembled

Bolaform Amphiphiles on

Cellulose

Sunkyu Park 1, Joseph J. Bozell 1, Josef Oberwinkler 2

June 14, 20071 Forest Products Center, University of Tennessee

2 Salzburg University of Applied Sciences, Salzburg, Austria

2007 International Conference

on Nanotechnology for the Forest Products Industry

2

3 Summary

2 Interaction Between Cellulose and Bolaforms

1What are Bolaform Amphiphiles?

1. Interaction on Cellulose

Surface

2. Interaction with Cellulose

Matrix

Presentation Contents

3

What are Bolaform What are Bolaform

Amphiphiles?Amphiphiles?

4

Bolaform Amphiphiles

Figure from Fuhrhop and Wang, Chem. Rev. 2004, 104, 2901-2937

5

Bolaforms as Self Assembling Systems

Figures from T. Shimizu, Macromol. Rapid Commun. 2002, 23, 311

6

Ferrier Bolaform Synthesis

Final product

7

Other Types of Bolaform Amphiphiles

8

Materials Used in this Study

Symmetric and C12 Bolaform Amphiphiles

Cellulose

9

Cellulose and Bolaform Cellulose and Bolaform AmphiphilesAmphiphiles

(1) Interaction (1) Interaction onon Cellulose Cellulose SurfaceSurface

10

• Materials– Cellulose: Microcrystalline cellulose (Avicel)

• Pretreatments– MeOH exchange ×3– DMAc exchange ×3

– Solvent• 8% LiCl in DMAc (N,N-dimethylacetamide)

– Solution• Cellulose + Bolaforms + LiCl/DMAc

• Methods– A drop on glass-slide– Drying– Polarized optical microscope

xx

Materials and Methods

11

Cellulose Film in Absence of Bolaforms

200µm

Cellulose film without bolaforms in LiCl/N,N-dimethylacetamide

12

Individualstructures

Bolaform Crystallization in Absence of Cellulose

200µm

Bolaforms without cellulosein LiCl/N,N-

dimethylacetamide

50µm

200µm 200µm

13

Bolaform Crystallization in Presence of Cellulose

200µm

Edge of drop

Bolaforms with cellulosein LiCl/N,N-

dimethylacetamide

200µm

14

Bolaform Crystallization Process

15

200µm

200µm 200µm

200µm

Different Crystal Structures

200µm

200µm

Without cellulose

16

FT-IR Imaging Characterization (1)

Image scanning

4000~650 cm-1 Image map at 2918 cm-1

17

FT-IR Imaging Characterization (2)

Multivariate analysis of cellulose-bolaforms pellets using statistics package

(Unscrambler)

18

Bolaform concentration mapping

FT-IR Imaging Characterization (3)

19

MeOH Washing

• MeOH washing– All bolaform crystals were immediately dissolved in

MeOH

20

Cellulose Film in Absence of Bolaforms

Solution:

Dissolved cellulose, LiCl/DMAc

Gel-type cellulose pad:

Cellulose pad, LiCl/ some DMAc, H2O

Formation mechanism

• Evaporation of DMAc

• Solidification of dissolved cellulose by H2O

21

Cellulose Film in Presence of Bolaforms

Formation mechanism

• Evaporation of DMAc

• Solidification of dissolved cellulose by H2O

• Individual bolaform crystal formation

• Deposition of individual bolaform crystals

(cellulose is acting as nucleating sites)

Solution:

Dissolved cellulose, LiCl/DMAc, Dissolved bolaforms

Gel-type cellulose pad:

Cellulose pad, LiCl/ some DMAc, H2O, Bolaform crystals

22

Cellulose as a Template for Assembly

Kondo et al, PNAS 2002, 99, 14008Kondo, 2007, Chap. 16 in Cellulose: Molecular and Structural Biology

23

200µm

200µm 200µm

200µm

Different Crystal Structures

200µm

200µm

Without cellulose

24

Control of Bolaform Crystallization

Formation mechanism

• Evaporation of DMAc

• Solidification of dissolved cellulose by H2O

• Individual bolaform crystal formation

• Deposition of individual bolaform crystals

Morphology of bolaform crystals in solvent

Template conditions of cellulose gel

Air flow

Cellulose concentration

Bolaforms concentration

Relative humidity

Temperature… more

25

MeOH Washing

(2) 0 min, 1st drop(1) 0 min (3) 15 min, 2nd drop

(4) 30min, 3rd drop

200µm

(5) 45 min, 4th drop

(6) 60 min, 5th drop

26

(7) 75min, 6th drop (8) 90 min, 7th drop

(9) After 95 min

90 min, before 7th drop

Bolaform Re-crystallization

27

Cellulose and Bolaform Cellulose and Bolaform AmphiphilesAmphiphiles

(2) Interaction (2) Interaction withwith Cellulose Cellulose MatrixMatrix

28

• Materials– Cellulose: Microcrystalline cellulose (Avicel)

• Pretreatments– MeOH exchange ×3– DMAc exchange ×3

– Solvent• 8% LiCl in DMAc (N,N-dimethylacetamide)

– Solution• Cellulose + Bolaforms + LiCl/DMAc

• Methods– Slow casting in Petri-dish– Washing with H2O– Drying at 60°C (restrained drying)– AFM, SEM, NMR, Sorption test

Materials and Methods

29

Cellulose-bolaform Film Preparation (1)

30

Cellulose-bolaform Film Preparation (2)

31

FT-IR: Multivariate Analysis

Multivariate analysis of bolaform-incorporated cellulose films

32

Film Surface: (1) AFM Images

Cellulose in DMAc/LiCl Bolaform/ Cellulose in DMAc/LiCl

33

Film Surface: (2) SEM Images

Cellulose Film Cellulose-Bolaform Film

34

Wide Angle X-ray Diffraction

X-ray source: CuKα (0.1542nm)

45kV and 0.66mA

Beam time: 30min

35

(110)/(020)

(103)(004)

(110)¯

Avicel

0% Bolaform Film

Bolaform powder

Diffraction Patterns for Powders/ Films

5% Bolaform Film

15% Bolaform Film

36

1D Integrated WAXD Profiles

Bolaform powder

Avicel powder

Amorphous cellulose powder

Cellulose film(bolaforms 0%)

Cellulose film(bolaforms 5%)

Cellulose film(bolaforms 15%)

5 10 15 20 25 30 35 40

2 theta, degree

37

Structural Information for Cellulose Films

• Crystallinity index, CI

• Crystal size, L

cos

kL

,%( )

Area of crystalline peaksCI

Area of crystalline amorphous peaks

k: Scherrer constant, 0.94

λ: x-ray wavelength

β: full-width at half-maximum

θ: Bragg angle

38

Bolaformconcentration,

%

Crystallinity

index, %

Crystal size,nm

R2 a) F b)

0% 35.5 2.36 0.9975 7038

1% 37.9 2.24 0.9982 8683

3% 36.7 2.24 0.9958 3587

5% 37.9 2.18 0.9943 2597

15% 39.1 2.18 0.9955 2303

Structural Information: Crystallinity, Crystal Size

a) and b) are regression coefficients during the curve fitting procedure

39

Low Resolution NMR

• Experimental Parameters– CPMG procedures

– τau 0.05 ms

– 256 echoes– 750 scans– 5 second recycle delay

40

NMR Relaxation Time

1.0

1.2

1.4

1.6

1.8

Cellulose 2%,Bolaform 0%

Cellulose 2%,Bolaform 5%

Cellulose 4%,Bolaform 0%

Cellulose 4%,Bolaform 5%

Rel

axat

ion

Tim

e, T

2 in

ms

41

SummarySummary

42

Summary

• Bolaform amphiphiles were successfully synthesized and the interactions with cellulose were studies.

• Highly-ordered self assembly of bolaform amphiphiles were observed on cellulose template, while individual self-assembled structures were found in the absence of cellulose.

• Bolaform-incorporated cellulose film showed higher relaxation time, which might be attributed to the interaction between cellulose hydroxyl groups and bolaform molecules.

43

• Thomas Elder– USDA-Forest Service– Southern Research Station– Pineville, LA

• Nicole Labbé– Forest Products Center– The University of Tennessee

• John R. Dunlap– Program in Microscopy– The University of Tennessee

Acknowledgements