MICROSTRUCTURE OF CHARGED MOSAIC MEMBRANES CONSTRUCTED BY PHASE GROWTH

A template pattern with alternating poly(4-vinylpyridine) (P4VP)/poly(vinyl alcohol) (PVA) lamellae was fabricated upon a cross-linked PVA film by casting of poly[4-vinylpyridine (4VP) -g-vinyl alcohol (VA)] graft copolymer. After a treatment involving the binding of a PVA film with the graft copolymer and also domain fixing of the PVA phases, a dilute solution of poly [ acrylic acid (AA)-benzyl N,N-dimethyldithiocarbamate (DMTC)] copolymer/P4VP binary blend was cast on this template surface. The microstructure of binary blend was observed from scanning electron microscopy (SEM) by wet-etching of films after domain fixing of one component of the binary blend. The poly (AA-DMTC) copolymer/P4VP binary microdomains formed by phase growth were oriented perpendicularly to the film surface. We also fabricated these charged mosaic regions on a microporous poly(vinyl chloride) (PVC) membrane, and carried out the surface analysis by X-ray photoelectron microscopy (XPS). Finally, we examined the transport of KCl through the charged mosaic composite membranes. (C) 1994 John Wiley & Sons, Inc.