Development of poly(vinylidene fluoride)/ionic liquid electrospun fibers for tissue engineering applications

Electroactive electrospun fiber mat composites based on poly(vinylidene fluoride) (PVDF) with 5 and 10 % of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([C2mim][NTf2]) ionic liquid (IL) were developed for potential applications in the biomedical area. The morphology and polymer crystalline phase content of the fibers were evaluated as a function of the processing conditions. Hydrophobic random and aligned fibers have been obtained with average fiber diameters between ~700 and 500 nm, the smaller diameters corresponding to the aligned fiber mats. The results show that the charge structure of [C2mim][NTf2] induces the crystallization of the PVDF fibers in the piezoelectric β-phase with full crystallization in this phase for an ionic liquid content of 10 wt%. Furthermore, the presence of the ionic liquid also increases the degree of crystallinity of the fibers. Thermal degradation studies show a single degradation process which is strongly influenced by the polymer–IL interactions. Finally, the non-cytotoxicity of the fiber mats indicates their suitability for biomedical applications.