In order to develop the membranes exhibiting high water flux with proper salt rejection for the reverse osmosis process, poly(m-aminostyrene-co-vinyl alcohol) (P(mAS-VA)) containing various amount of VA was explored as a new polymeric materials for the barrier layer of the thin-film composite membranes. P(mAS-VA) copolymers were prepared by reducing poly(m-nitrostyrene-co-vinyl acetate) (P(mNS-VAc)) that was synthesized by the free radical reaction of m-nitrostyrene (mNS) and vinyl acetate. The water flux of membranes prepared by interfacially reacted P(mAS-VA) with trimesoyl chloride (TMC) continuously increased with VA content in copolymer, while decline in the salt rejection was not serious. The performance of membranes prepared from TMC and a mixed solution of m-phenylene diamine (MPDA) and P(mAS-VA) was also investigated. Membranes examined here showed performance advantage over the trade-off trend between water flux and salt rejection. (C) 2003 Elsevier Science B.V. All tights reserved.