Graduate School of Engineering, Shinshu University Master’s degree Osamu Ohsawa

1. Study on the Poly(ether ketone)(PK) nanofibrous membrane via electrospinning Graduate School of Engineering, Shinshu University Master’s degreeOsamu 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) 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. Large surface area Small pore size High porosity 3D structure of E-spun fibers Features & Applications of Nanofiber Web Electromagnetic shielding Liquid crystal device Tissue Template Composite Filtration Medical Prosthesis Ref. Z. Huang et al. Comps. Sci. Technol. 2003, 63, 2223.

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 Applied voltage: 10kV Polymer: Poly(ether ketone)(IV:2.3) 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 12wt% 2μm 2μm 2μm 10wt% 2μm 8wt% 6wt%

9. Solution properties & Morphologies 100% Effect of mixture solvent 75% 40% 30% 2μm 2μm 2μm 2μm TFA content(%) Optimum condition Concentration:12wt% TFA/MC=40/60, 50/50

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

11. Crystal structure Intermolecular dipole-dipole bonds Intermolecular hydrogen bonds α form β form Transformation condition α→β Fabrication method (Spinning, Drawing) Crystallization kinetics Temperature etc… b a b a

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

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

14. Raman -CH2- symmetric stretching(νs) -CH2- asymmetric stretching(νa) C=Ostretching (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 1440cm-1 α-form β-form 1412cm-1 1418cm-1 1430cm-1 Solvent cast PK film Electrospun PK fiber 1350 1400 1450 -1 Wavenumber(cm )

16. FT-IR 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 Stretched Gel-spun PK fiber Gel-spun PK fiber Electrospun PKfiber 0 10 20 30 40 50 2theta (o)

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