Am amphiphilic comb-like copolymer consisting of a poly(vinyl chloride) (PVC) backbone and poly((oxyethylene)(9) methacrylate) (POEM) side chains, PVC-graft-POEM was synthesized via atom transfer radical polymerization. This comb copolymer was complexed with LiCF3SO3 to form a solid polymer electrolyte. FTIR and FT-Raman spectroscopy indicate that lithium salts are dissolved in the ion conducting POEM domains of microphase-separated graft copolymer up to 10 wt % of salt concentration. Microphase-separated structure of the materials and the selective interaction of lithium ions with POEM domains were revealed by transmission electron microscopy, wide angle X-ray scattering, and differential scanning calorimetry. The maximum ionic conductivity of 4.4 x 10(-5) S/cm at room temperature was achieved at 10 wt % of salt concentration, above which salts are present as less mobile species such as ion pairs and higher order ionic aggregates, as characterized by FT-Raman spectroscopy. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1443-1451, 2009