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 tetraethylorthosilicate within the cluster morphology of perfluorosulfonic acid films. Small-angle x-ray scattering revealed that the polar/nonpolar nanophase-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 near the surface and decreases to a minimum in the middle. Optical and ESEM micrographs revealed a brittle, surface-attached silica layer at high silicon oxide contents. (C) 1995 John Wiley & Sons, Inc.