CONDUCTIVITY AND 1H NMR STUDIES ON PVP: NH4Br POLYMER ELECTROLYTE

Proton conducting polymer electrolytes based on Poly (N-vinyl pyrrrolidone) and Ammmonium Bromide (NH4Br) have been prepared in different compositions by solution casting technique. The prepared polymer electrolytes have been characterised by the experimental techniques such as XRD, DSC, AC Impedance Spectroscopy and H-1 NMR. The XRD analysis reveals the amorphous nature of the polymer electrolyte. The DSC analysis shows that the glass transition temperature of the polymer complexes decreases upon addition of NH4Br salt indicating the interaction between the polymer and the salt. AC impedance analysis has been carried out to find the best composition possessing good electrical and mechanical stability. The maximum protonic conductivity at room temperature has been found to be 1.06x10(-3) S cm(-1) for 25 mol% salt doped electrolyte and the electrolyte obeys the Arrhenius behaviour. 1HNMR study has been carried out on the prepared polymer electrolytes to have a better understanding of the ion transport mechanism. H-1 NMR study indicates that the NH4+ ion is responsible for the proton conduction.