Proton conducting polymer electrolytes on the basis of poly(vinylphosphonic acid) and imidazole Original Research Article

Anhydrous proton conducting polymer electrolytes have been prepared by doping of poly(vinylphosphonic acid) (PVPA) with imidazole (Im) in with various stoichiometric ratios, x, to form PVPA x Im where x is the number of moles of Im per moles of polymer repeat unit. Polymer electrolytes, PVPA x Im (with x=0.5, x=1 and x=2) can be cast into transparent, homogeneous films. FT-IR results indicate the transfer of acidic protons to imidazole units to form imidazolium ions. Thermogravimetric analysis illustrates that these blends are thermally stable up to about 150 °C. The glass transition temperatures of the blends were detected via differential scanning calorimetry. DC conductivity increases with doping ratio of Im reaching ∼5×10−3 S/cm for x=2 at 130 °C.