Proton conducting blends of poly(4-vinylimidazole) with phosphoric acid

Abstract

The synthesis, thermal, and conduction properties of blends prepared from poly(4-vinyl-imidazole), P-4VI, and phosphoric acid are reported. The number of moles of phosphoric acid per polymer repeat unit, x, was varied from 0≤x≤2. These blends can be cast into homogeneous films. Thermogravimetric analysis (TGA) illustrates that these blends are chemically stable up to about 150 °C. Differential scanning calorimetry (DSC) shows that the softening temperature of the blends decrease from 77 °C for x = 1 to -8 °C for x = 2. The DC conductivity increases with x and reaches approximately 10-4 S/cm for x = 2 at ambient temperature.