| Summary: | 博士 === 國立臺灣科技大學 === 高分子系 === 98 === The objectives of this study are to optimize the parameters of electrospinning (ES) poly(vinylidene fluoride) (PVDF) using a co-solvent system of N,N-dimethylformamide(DMF) and acetone, and to blend with polylactide (PLA) and Pluronic F127 to spin into nanoscale nonwoven mats which may improve the elongation, hydrophilicity, and biocompatibility of PVDF for applying in biomatrix, filter, or battery seperation.
The physical properties of the resulting mats were subjected to characterization including scanning electron microscope (SEM), Fourier transform infrared spectrometer (FTIR), wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), capillary flow porometer, contact angle, tensile test, and the biocompatibility based on blood coagulation time (APTT&PT) and cell proliferation of L929 fibroblast.
In the first section, using a co-solvent system of DMF/acetone at a ratio of 90:10, the average fiber diameter of PVDF mat achieved 184 nm without beads and CV=0.40. Thus these parameters were applied to the following sections.
In the second section, PLA was mixed with PVDF and spun into nonwoven mats via electrospinning technique using DMF/acetone as the co-solvent. The viscosity of the solution was measured, and the average fiber diameter achievable without beads for PLA, PVDF/PLA, and PVDF mats were 191 nm, 215 nm, and 184 nm, respectively. Infrared (IR) spectra showed that electrospinning can induce β phase crystallization of PVDF. From the results of DSC, the PVDF/PLA mats exhibited higher melting temperature but lower crystallinity than both PLA and PVDF. The tensile strength of PVDF/PLA was lower than those of PLA and PVDF. By stretching during eletrospinning, the ratio of strength in machine direction (MD) to that in cross direction (CD) was increased to 2. In addition, electrospun PVDF/PLA mats exhibited higher cell proliferation for L929 fibroblasts than both PLA and PVDF mats.
In the final section, PVDF was blended with Pluronic F127 and spun into nanofibers via electrospinning (ES) process using a co-solvent of DMF and acetone with a ratio of 90/10. The average diameters of the resulting PVDF/F127 nanofibers ranged from 300 to 500nm (avg. dia=372nm, CV=0.30). The embedding of F127 in PVDF matrix was evidenced by EDX, IR spectra. The blending of F127 not only improved the hydrophilicity of PVDF nanofiber (contact angle was decreased from 125° to 54.7°) but also reduced the pore size. In addition, F127 can serve as the binding agent for the electrospun nanofibers to improve its tensile strength and breaking elongation. Furthermore, L929 fibroblasts proliferated on the electrospun PVDF/F127 mats. These results indicate that the electrospun PVDF/F127 nanofiber is a potential substrate for tissue engineering scaffolds.
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