Ionic conduction in plasticized PVC/PMMA blend polymer electrolytes

The new plasticized polymer electrolyte composed of the blend of poly(vinyl chloride) (PVC) and poly(methyl methacrylate) (PMMA) as a host polymer, the mixture of ethylene carbonate and propylene carbonate as a plasticizer, and LiCF3SO3 as a salt was studied. The effect of the PMMA/PVC blend ratio and the plasticizer content on the ionic conductions in these electrolytes were investigated. The electrolyte films revealed a phase separated morphology due to immiscibility of the PVC with the plasticizer; the PVC-rich phase and the plasticizer-rich phase were produced during the film casting. The mechanical property was significantly enhanced by the incorporation of PVC into the electrolyte system. The ionic conductivity decreased with increasing the PVC/PMMA ratio and increased with increasing the plasticizer content. These behaviors were explained in terms of the morphology of the film. Since the plasticizer-rich phase contains much more plasticizer than the PVC-rich phase, the ions preferentially move through plasticizer-rich phase. Due to the slow ionic transport through the PVC-rich phase, the conductivity decreased with increasing PVC/PMMA ratio. (C) 1997 Elsevier Science Ltd.