Synthesis and ionic conductivity studies of solid polymer electrolytes based on modified alternating maleic anhydride copolymer with oligo(oxyethylene) side chains

Comb-like polymers (CP) based on modified alternating methyl vinyl ether/maleic anhydride copolymer with oligo-oxyethylene side chains of the type O(CH₂CH₂O)_nCH₃ have been synthesized and characterized, and complexed with LiNO₃ to form an amorphous polymer electrolyte. CP/salt complexes showed conductivity up to 10⁻⁵ S/cm at room temperature. The temperature dependence of ionic conductivity suggests that the ion transport is controlled by segmental motion of the polymer, shown by linear curves obtained in Vogel–Trammann–Fulcher plots. The ionic conductivity maximum moves to a higher salt concentration as the temperature increases. IR results also indicate that the ester in CP might decompose at 140°C and reproduce the maleic anhydride ring.