Dehydrohalogenated poly(vinylidene fluoride)-based anion exchange membranes for fuel cell applications

Abstract

The anionic membrane based on poly(vinylidene fluoride) (PVDF) has been successfully synthesized by grafting of vinyl benzyl trimethyl ammonium chloride. The chemical grafting has been confirmed through the spectroscopic techniques such as FTIR, NMR, and UV–visible. Morphological studies through the scanning electron microscope and atomic force microscope also indicate the changes in surface topography. Structural transformation was studied using XRD and DSC measurements, and the deconvolution analyses indicate the phase fraction of the functionalized membrane as compared with pristine PVDF. The polar/partial polar phase (β+γ), responsible for piezoelectricity, is found to be 64% for a functionalized membrane. The mechanical stability and glass transition temperature of the functionalized membrane are determined using dynamic mechanical measurement. Membrane characteristics such as water uptake (14.2%), ion exchange capacity (0.91 mmol/g), ion conductivity (0.52 mS/cmat 25 °C), and lower activation energy value of 28.31 kJ/mol of the functionalized membrane indicate the suitable electrolyte for alkaline fuel cells, and the creation of the piezoelectric phase indicates the possibility of a smart membrane for various technologies.