Investigation of proton conductivity of anhydrous proton exchange membranes prepared via grafting vinyltriazole onto alkaline-treated PVDF

This work uses a simple “grafting through” approach in the preparation of anhydrous poly(vinylidene fluoride) (PVDF)-g-PVTri polymer electrolyte membranes (PEMs). Alkaline-treated PVDF was used as a macromolecule in conjunction with vinyltriazole in the graft copolymerization. The obtained polymer was subsequently doped with triflic acid (TA) at different stoichiometric ratios with respect to triazole units and the anhydrous PEMs (PVDF-g-PVTri-(TA)_x) were prepared. All samples were characterized by FTIR and ¹H NMR. The composition of PVDF-g-PVTri was determined by energy dispersive spectroscopy. Thermal properties of the membranes were examined by thermogravimetric analysis and differential scanning calorimetry. The surface roughness and morphology of the membranes were studied using atomic force microscopy, X-ray diffraction, and scanning electron microscopy. PVDF-g-PVTri-(TA)₃ (C3-TA₃) with a degree of grafting of 47.22% showed a maximum proton conductivity of 0.09 S cm⁻¹ at 150 °C and anhydrous conditions. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1885–1897