Study of ion-molecule interaction in poly(metylmethacrylate) based gel electrolytes by Raman-spectroscopy

Gel electrolytes based on polymethymetacrylate (PMMA) have been obtained using propylene carbonate and ethylene carbonate as gelating agents. They have a good mechanical stability, solvent retention and high electrical conductivity at room temperature (about 10(-3) Sem(-1)). In the aim of understanding the possible interactions of the mobile ions with polymer or solvent molecules, a comparative Raman study has been carried out on samples containing all the components of the gel electrolytes or some of them. The interaction with Li+ ions induces appreciable 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 carbonate ring. The change in size and polarizability of the anion species does not affect such cation-solvent interaction