Nanocomposite polymer electrolyte membranes based on poly (vinylphosphonic acid)/sulfated nano-titania

Proton conductors comprising phosphonic acid units are very promising due to their oxidative stability as well as high proton conductivity. In the present work, the membrane materials were produced by mixing of poly(vinylphosphonic acid) (PVPA) with sulfated nano-titania at various concentrations to get PVPATSx where x designates the molar ratio of the polymer repeating units to sulfate units (varied from 1 to 4). The structure of the nanocomposite polymer membrane is confirmed by FT-IR spectroscopy. The TGA results verify that the presence of sulfated nano-titania in the complex polymer electrolytes suppressed the formation of phosphonic acid anhydrides up to 200 °C. DSC results indicate that the Tg of the materials shifts to higher temperatures as sulfated nano-titania content increases. In the anhydrous state, the proton conductivity of PVPATS is found to be 0.03 (S cm−1) at 150 °C. Proton conductivity of these membranes are also measured and compared with previous studies. The results suggest that proton conduction is occurred between surface of the nano-titania particles with the aid of sulfonic acid and phosphonic acid units.

► Nanocomposite electrolytes containing poly(vinylphosphonic acid) and sulfated nano-titania were prepared. ► The proton conductivity of PVPATS has been found to be 0.03 (S cm−1) at 150 °C. ► As acid-modified oxide composite membranes, its conductivity, structural, and morphological investigation were done.