This paper Studied the synthesis of a novel elastomeric copolymer electrolyte in an aqueous phase. The monomer, sodium allyl sulfonate (SAS), was dissolved in continuous aqueous phase and the second monomer, methyl acrylate (MA), was supplied from MA micelles as dispersed phase. The copolymerization of the two monomers took place in continuous aqueous phase. Confirmed by FTIR and H-1-NMR, a binary copolymer electrolyte of MA and SAS, poly(MA-co-SAS), was obtained. The glass transition temperature of the copolymer was indicated as 20.4 degrees C by DSC thermogram, thus, it behaves an elastomer in normal ambient temperature. The mechanical properties of the composite films consisting of both poly(MA-co-SAS) and Cu2+ ions or reduced copper were affected by the content of ions and reduced copper. (c) 2006 Wiley Periodicals, Inc.