Abstract
A series of composite membranes based on mono sulfonated poly(ether sulfone) (SPES) embedded with silicotungstic acid (STA) was synthesized. SPES was synthesized by nucleophilic aromatic polymerization and solution blended with silicotungstic acid. Direct synthesis of sulfonated polymer controls the degree of sulfonation and this leads to higher thermal stability. The composite membranes were characterized for water uptake, swelling ratio, ion-exchange capacity, thermal stability and proton conductivity for evaluating the suitability of these membranes for fuel cells. The proton conductivity of the composite membranes was increased with increasing STA content. The conductivity of the composite membranes at 30°C was increased from 0.082 S/cm to 0.095 S/cm, whereas the parent membrane shows 0.078 S/cm. The composite membranes not only have good proton conductivity, but also showed excellent thermal stability. This study shows that the composite membranes based on SPES and STA can be viable candidates for electrolyte membranes.