We report the preparation and characterization of binary blend films of poly(vinylidene fluoride) (PVDF) and poly(1- ethyl-3-vinylimidazolium trifluoromethylsulfonylimide) (PVIm
TFSI-) derived from ionic liquid imidazolium monomers and doped with TFSI- salt. The potential utility of such materials in capacitive electronic devices and in proton exchange membrane fuel cells is of particular interest. Thin PVDF/ PVIm
TFSI- films were fabricated from solutions of dimethly formamide (DMF) by doctor blading. The nature of the PVDF crystalline polymorph and degree of crystallinity were evaluated as a function of the volume fraction of imidazolium polymer and thermal treatment. The morphology, thermal and mechanical characteristics and crystallinity of PVDF, in semicrystalline blend films was studied by wide angle X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetry, and dynamic mechanical analysis. In these materials, conditions such as choice of solvent, drying conditions, and thermal treatment affect the crystal phase, crystallite size, and degree of crystallinity of PVDF as well as the distribution of the minor component, the vinylimidazolium polymer. The polar beta phase of PVDF crystals dominates in as-cast films, while the non-polar alpha phase is observed after cooling from the melt. PVDF imparts mechanical strength and chemical stability to the composite films, and because of its high crystal melting point (Tm > 160 °C), serves to improve the high temperature stability of resulting films.