Proton exchange nanocomposite membranes based on 3-glycidoxypropyltrimethoxysilane, silicotungstic acid and α-zirconium phosphate hydrate

Novel fast proton-conducting GPTS-STA-SiO2 and GPTS-STA-ZrP composites were successfully fabricated. The polymer matrix obtained through hydrolysis and condensation reaction of 3-glycidoxypropyltrimethoxysilane (GPTS) showed apparent proton conduction at high relative humidity with conductivity from 1.0 X 10(-7) to 3.6 X 10(-6) S/cm, although no proton donor was incorporated. The proton conductivities of the fabricated composites were high, and increased up to 1.9 X 10(-2) S/cm by addition of silicotungstic acid (STA). By incorporating alpha -zirconium phosphate (ZrP) into the GPTS-STA polymer matrix, the composite showed increased conductivity at low temperature (similar to 80 degreesC), indicating weak dependence on humidity by molecular water in ZrP, The high proton conductivity of the composites is due to the proton conducting path through the GPTS-derived 'pseudo-polyethylene oxide (pseudo-PEO)' networks, which also contains a trapped solid acid (silicotungstic acid) as a proton donor. (C) 2001 Elsevier Science B.V. All rights reserved.