Characterization of proton conducting polymer blend electrolytes based on PVdF-PVA

Abstract

The polymer electrolytes composed of poly (vinylidene fluoride) PVdF and poly (vinyl alcohol) PVA with various ratios of ammonium thiocyanate(NH4SCN) salt have been prepared by solution casting method. The increase in amorphous nature of polymer electrolytes has been confirmed by XRD analysis. The polymers-salt interactions have been analysed by FTIR spectroscopy. The Scanning Electron Micrographs affirm the smooth morphology of the polymer electrolytes. A shift in glass transition temperature (Tg) of the electrolytes has been observed from the DSC thermograms which indicates the interaction between polymers and salt. The conductivity and dielectric measurements are carried out on these films as a function of frequency at various temperatures. From the complex impedance spectroscopy, the conductivity is found to increase in the order of 10−9 to 10−3 S/cm at room temperature with the increase in salt concentration. The ionic transference number of the mobile ions has been estimated by Wagner's polarization method and the results reveal that the conducting species are predominantly due to ions.