Mechanical properties and biocompatibility of electrospun polylactide/poly(vinylidene fluoride) mats

Polylactide (PLA) was mixed with poly(vinylidene fluoride) (PVDF) and spun into nonwoven mats via electrospinning technique using a co-solvent system of N,N-dimethylformamide (DMF) and acetone. The resulting mats were subject to characterization including contact angle, infrared spectrometry (IR), wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), tensile test, and examined using scanning electron microscope (SEM). With such a co-solvent system, the viscosity was measured, and the average fiber diameter achievable without beads for PLA, PLA/PVDF, and PVDF mats was 252 nm, 209 nm, and 355 nm, respectively. Infrared spectra showed that electrospinning can induce crystallization of PVDF. Both alpha and beta phases were observed from the IR and WAXD results. From the results of DSC, the PLA/PVDF mats exhibited higher melting temperature but lower crystallinity than both PLA and PVDF. The tensile strength of PLA/PVDF was lower than those of PLA and PVDF. By applying stretching during eletrospinning, the ratio of strength in machine direction (MD) to that in cross direction (CD) was increased to 2. In addition, electrospun PLA/PVDF mats exhibited higher cell proliferation for L929 fibroblasts than both PLA and PVDF mats.