Hybrid Network Sulfonated Polynorbornene/Silica Membranes with Enhanced Proton Conductivity by Doped Phosphotungstic Acid



A series of novel hybrid sulfonated polynorbornene-silica (PBN–SiO2) proton conducting membranes doped with different weight ratio of phosphotungstic acid (PWA) were prepared by the casting procedure. The proton conductivity of the composite membranes containing 40 wt.% PWA reached the maximum of 6.1 × 10–2 S cm–1 and increased gradually with PWA content and temperature elevating, while the methanol permeabilities (3.52–9.39 × 10–7 cm2 s–1) of these membranes were much lower than that of Nafion 117 (2.36 × 10–6 cm2 s–1). The membranes also exhibited excellent thermally stable and mechanical properties, which imply that the PBN–SiO2–PWA membranes are promising materials in the direct methanol fuel cells (DMFC) applications.