Sulfonated dimethyl fumarate (SDMF) was prepared with dimethyl fumarate (DNF) and sodium hydrogensulfite (NaHSO3). Sodium sulfonate side-chain poly(ethylene oxide) (SPEO) was synthesized by grafting sodium sulfonate onto the chain of PEO with molecular weights of 400, 600, 800, and 1000. SPEO was used subsequently in step-growth polymerization to give a polyurethane ionomer (SPU). Samples were characterized by element analysis, FTIR, H-1-NMR, EDX mapping, X-ray, gel permeation chromatography, and impedance analysis. The SPUs exhibited an amorphous structure. The maximum conductivity of the SPU was 1.02 x 10(-6) S cm(-1) at the room temperature.