Proton-Conducting Properties of Inorganic-Organic Nanocomposites Proton-Exchange Nanocomposite Membranes Based on 3-Glycidoxypropyltrimethoxysilane and Tetraethylorthosilicate

Novel fast proton-conducting organic-inorganic hybrid nanocomposites were successfully fabricated. The polymer matrix obtained through a hydrolysis and condensation reaction of 3-glycidoxypropyltrimethoxysilane (GPTS) and tetraethylorthosilicate showed relatively high proton conductivity, over at 100% RH, at 20-100°C, although a proton donor was not incorporated. The proton conductivities of the fabricated composites were high and increased up to by addition of silicotungstic acid at 100% RH and 100°C. The high proton conductivity of the composites is due to the proton-conducting path through the GPTS-derived "pseudopolyethylene oxide (pseudo-PEO)" networks in which the trapped solid acid (silicotungstic acid in this study) as a proton donor is contained. The molecular water absorbed in the polymer matrix is also presumed to provide high proton mobility, resulting in an increase of proton conductivity.