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 ([C(2)mim][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 similar to 700 and 500 nm, the smaller diameters corresponding to the aligned fiber mats. The results show that the charge structure of [C(2)mim][NTf2] induces the crystallization of the PVDF fibers in the piezoelectric beta-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.