MICROSTRUCTURAL EVOLUTION OF A SILICON-OXIDE PHASE IN A PERFLUOROSULFONIC ACID IONOMER BY AN IN-SITU SOL-GEL REACTION

Nanocomposites were produced via sol-gel reactions for tetraethylortho silicate within the cluster morphology of perfluorosulfonic acid films . Small-angle x-ray scattering revealed that the polar/nonpolar nanoph ase-separated morphological template persists despite invasion by the silicon oxide phase. Scanning electron microscopy (ESEM-EDAX) studies have indicated that the greatest silicon oxide concentration occurs ne ar the surface and decreases to a minimum in the middle. Optical and E SEM micrographs revealed a brittle, surface-attached silica layer at h igh silicon oxide contents. (C) 1995 John Wiley & Sons, Inc.