A new ion-exchange membrane was prepared by blending a copolymer of poly(styrene sulfonic acid-co-N-(2-hydroxyethyl) acrylamide) with poly(vinylidene fluoride). The dissolution of the copolymer into water was prevented by the crosslinked network formed by condensation reaction between N-(2-hydoroxyethyl) acrylamide (HEAA) units. The reaction was caused after film-forming the blend. Swellability in water, ion-exchange capacity, ion conductivity, and mechanical properties of the membrane were investigated and compared with those of a well-known ion-exchange membrane, Nafion 117. (c) 2006 Wiley Periodicals, Inc.