1. Study on the Poly(ether ketone)(PK) nanofibrous membrane via electrospinning
Graduate School of Engineering, Shinshu University
Master’s degree Osamu Ohsawa

2. Reserch Topics
Characterization of PK nanofibrous membrane via electrospinning
Property comparison between electrospun PK nanofiber and Gel-spun PK microfiber

3. Poly(ether ketone) Properties: fast crystallization
CYBERLONTM
Properties:
fast crystallization
high tensile strength
high chemical and wear resistance
very low permaeability
good impact behavior over a broad temperature range

4. Electrospinning & Gel-spinning

5. Features & Applications of Nanofiber Web
Large surface area
Small pore size
High porosity
Ref. Z. Huang et al. Comps. Sci. Technol.
2003, 63, 2223.
Medical Prosthesis
Filtration
Composite
Tissue Template
Liquid crystal device
Electromagnetic shielding
3D structure of E-spun fibers

6. Electrospinning parameters
Solution properties
→ Viscosity (centipoise)
→ Conductivity (μS/cm)
→ Surface tension (dyne/cm)
Controlled variables
→ Hydrostatic pressure in the capillary
→ Applied voltage
→ Tip-to-collector distance
Ambient parameters
→ Temperature, Humidity
→ Air velocity in the electrospinning chamber

7. Experimental Materials Conditions Polymer: Poly(ether ketone)(IV:2.3)
Applied voltage: 10kV
Solvents: Trifluoroacetic acid (TFA)
dichloromethane (MC)
Tip-to Collector distance: 15cm
Solution concentration:6-14wt%
Temperature: RT
Mixture solvent ratio (TFA/MC,w/w)
: 30/70, 40/60, 50/50, 75/25, 100/0
Humidity: 40%

8. Solution properties & Morphologies
Effect of concentration
2μm
6wt%
8wt%
10wt%
12wt%
Concentration
Viscosity
Surface tension
[wt%]
[cP]
[mN/m] 6 90
20.9 8
234
22.2 10
541.4
23.2 12
943.3
23.9 14
1725
24.7

9. Solution properties & Morphologies
30%
40%
75%
100%
Effect of mixture solvent
TFA content(%)
Optimum condition
Concentration:12wt%
TFA/MC=40/60, 50/50

10. Time dependence of PK solution0h 5h
10h
24h 0h 5h
10h
24h
2μm
2μm
2μm
2μm

11. Crystal structure α form β form b b a a Intermolecular
dipole-dipole bonds
Intermolecular
hydrogen
bonds
α form
β form
Fabrication method (Spinning, Drawing)
Transformation condition α→β
Temperature
Crystallization kinetics
etc…
a (Å)
b (Å)
c (Å)
ρc(g/cm3) α
6.87
5.12
7.6
1.39 β
8.24
4.74
7.58
1.26

12. WAXD α α α α α α α Intensity (a.u.) β β 2theta (degree) 10 20 30 40 50
(110)
(301)
(210)
(200)
(111)
(101)
(103)
(212) α
Intensity (a.u.) α α α α α α β
Solvent cast PK film β
(201)
(210)
Electrospun PK fiber 10 20 30 40 50
2theta (degree)

13. DSC α→β Heat Flow (J/g) Temperature (oC) 50 100 150 200 250 300
Solvent cast PK film 50
100
150
200
250
300
Electrospun PK fiber
Heat Flow (J/g)
Crystallinity
1J/g
E-spun fiber: 48%
Solvent cast film: 56%
Temperature (oC)

14. Raman Wavenumbers (cm-1) 1000 1200 1400 1600 1800
-CH2- symmetric stretching(νs)
-CH2- asymmetric stretching(νa)
C=O　stretching (ν)
-CH2- bending(δ)
2700
2800
2900
3000
3100
-CH2- twisting(γt)
C-C stretching(ν)
Solvent cast PK film
Electrospun PK fiber
1000
1200
1400
1600
1800
Wavenumbers (cm-1)

15. Raman Wavenumber(cm ) α-form β-form 1440cm-1 1412cm-1 1418cm-1
Solvent cast PK film
Electrospun PK fiber
1350
1400
1450
Wavenumber(cm -1 )

16. FT-IR Transmittance (%) Wavenumbers (cm-1) 4000 3500 3000 2500 2000
Solvent cast PK film
Electrospun PK fiber
-CH2-
symmetric stretching (νs)
-CH2-
twisting
Transmittance (%)
Skeletal
vibration
-CH2-
bending(δ)
inter unit CC
stretching(ν)
-CH2-Wagging 5%
ν (C=O)
4000
3500
3000
2500
2000
1500
1000
500
Wavenumbers (cm-1)

17. Conclusion
PK nanofibers have been successfully electrospun from the solution.
The optimized concentration and mixture solvent ratio of the solution for electrospinning were 12wt% and TFA/MC (40/60,w/w), respectively.
Different crystalline forms of electrospun PK fiber and solvent cast PK film were confirmed by XRD, FT-IR, and Raman spectroscopy.
Solvent cast PK film showed completely α-form, while electrospun PK
fiber showed β-form, suggesting the different crystallization kinetics and stress induced crystalline transformation during electrospinning and solvent casting process.

18. Thank you for your attentions!!

19. WAXD Intensity 1000 2theta (o) Stretched Gel-spun PK fiber10 20 30 40 50
Intensity
2theta (o)
1000
Gel-spun PK fiber
Electrospun PK fiber
Stretched Gel-spun PK fiber

20. FT-IR Transmittance (%) Wavenumbers (cm-1) 5 4000 3500 3000 2500 2000
1500
1000
Wavenumbers (cm-1)