TRANSPORT OF ELECTROLYTES THROUGH CHARGE MOSAIC COMPOSITE MEMBRANES

A template pattern with alternating poly(4-vinylpyridine) (P4VP)/poly(vinyl alcohol) (PVA) lamellae was fabricated upon a microporous membrane by casting of poly[4-vinylpyridine(4VP)-g-vinyl alcohol(VA)] graft copolymer from a water-1-propanol mixture. After a treatment involving the binding of the microporous membrane with the graft copolymer and also domain fixing of the PVA phases, a dilute solution of poly[sodium p-styrenesulfonate(SSS)-g-VA] graft copolymer/P4VP binary blend was cast on this template surface. The poly(SSS-g-VA)/P4VP binary microdomains formed by phase growth were oriented perpendicularly to the film surface. After chemical treatments (introduction of a positive charge and domain fixing of ion-exchange regions), we characterized these charge mosaic composite membranes in detail. Subsequently, we examined the transport of KCl and selective transport of a KCl-sucrose mixture through the charge mosaic composite membranes as a function of the thickness of the charged mosaic regions.