STUDY OF ION-MOLECULE INTERACTION IN POLY(METHYLMETHACRYLATE) BASED GEL ELECTROLYTES BY RAMAN-SPECTROSCOPY

Gel electrolytes based on polymethymetacrylate (PMMA) have been obtain ed using propylene carbonate and ethylene carbonate as gelating agents . They have a good mechanical stability, solvent retention and high el ectrical conductivity at room temperature (about 10(-3) Sem(-1)). In t he aim of understanding the possible interactions of the mobile ions w ith polymer or solvent molecules, a comparative Raman study has been c arried out on samples containing all the components of the gel electro lytes or some of them. The interaction with Li+ ions induces appreciab le modifications of the vibrational spectra of the solvent molecules; two new bands appear at 900 cm(-1) and 730 cm(-1), slightly upshifted with respect to the stretching and bending modes of the ethylene carbo nate ring. The change in size and polarizability of the anion species does not affect such cation-solvent interaction.