Plasticized single-ion polymer conductors: Conductivity, local and segmental dynamics, and interaction parameters

This paper considers high-quality conductivity data for plasticized ionomers in the context of polymer local and segmental processes. Dielectric spectroscopy was conducted on a neat PEO-based ionomer and six mixtures containing 6 wt % plasticizer with a wide range of dielectric constants. Conductivity increased dramatically but remained Vogel Fulcher Tamman (VFT)-like for all plasticized ionomers, indicating that the mechanism of ion transport was unchanged. Relaxation times of the polymer local β and segmental α processes were analyzed for the plasticized ionomers, providing activation energies and relaxation strengths for the β process and VFT fitting parameters for the a process. The glass transition temperature T _g of the mixtures was found to be the critical characteristic governing conductivity, based on four criteria: VFT-like behavior of conductivity, decrease in the conductivity-segmental coupling index upon the addition of plasticizer, statistical insignificance of solvent quality (dielectric constant, donor number, and viscosity) on conductivity, and the creation of a conductivity master curve as a function of T_g- normalized temperature.