Films prepared from poly(isoprene-b-styrene-b-isoprene-b-(4-vinylbenzyl)dimethylamine-i>isoprene) (ISIAI) pentablock copolymers were subjected to chemical modification: the A block was quaternized, the I block cross-linked, and the S block sulfonated, in that order. The three-layer lamellar structures of the original films were retained through these processes. The resulting membranes had substantial cationand anion-exchange capacities and cation transport numbers near 0.50 for KC1. They exhibited a piezodialytic effect and negative osmosis as predicted for a "charge-mosaic" membrane.
A charge-mosaic membrane was prepared from a pentablock copolymer of the BABCB type by selectively introducing anion and cation exchange groups into the microseparated phases. The three-layer lamellar structure of the starting pentablock copolymer film was not disturbed by the modifications. The membrane obtained was highly permeable only to sodium chloride in mixed aqueous solutions of sodium chloride and organic species of low molecular weight, such as sucrose. Marked pH-dependent permeabilities were also observed for amino acids.
Water and salt transports through a charge-mosaic membrane prepared from a pentablock copolymer of the ISBAI type were investigated by using aqueous solutions of KC1. The membrane showed a very high permeability for KC1, pronounced negative osmosis, and piezodialysis. The data were analyzed according to the phenomenological equation by Kedem and Katchalsky.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.