Conductivity Enhancement of (Epoxidized Natural Rubber 50)/Poly(Ethyl Methacrylate)-Ionic Liquid-Ammonium Triflate

The present work investigates the role of ionic liquid, 1-butyl-3 methyl imidazolium tetrafluoroborate in enhancing the conductivity of polymer electrolyte system of epoxidized natural rubber 50/poly(ethyl methacrylate)-ammonium triflate. Fourier transform infrared spectroscopic study shows evidence of interaction between epoxidized natural rubber 50, poly(ethyl methacrylate), ionic liquid and ammonium salt. Addition of ammonium salt to the epoxidized natural rubber 50/poly(ethyl methacrylate)-ionic liquid system increases the glass transition temperature indicating reduction in flexibility of the host polymer chains due to formation of transient cross-linking. However, the room temperature ionic conductivity of the polymer electrolyte increases with salt content about an order of magnitude compared to the system without ionic liquid. The results of this work show that the ionic liquid in this polymer electrolyte system acts as plasticizer which assists dissolution and dissociation of the doping salt, resulting in higher concentration of charge carriers. The activation energy result reveals that the presence of ionic liquid weakens the interactions between polymer chains and cation from the ammonium salt.