The conductivity of the novel PTFE polymer electrolytes

The dc conductivities of the novel PTFE (XUS series) ionomers having various water concentrations were measured by ac impedance method to study the effect of water molecules in assisting the ionic conduction. It was found that the conductivity increases drastically by moisture uptake, and the enhancement of conductivity by water molecules is larger at small sorption of the ionomer. Except for dried specimen, all logarithmic plots of ionic conductivities against reciprocal temperatures show a convex curvature, featuring the VTF behavior with a cutoff temperature which decreases as the moisture content increases. It is speculated that the presence of water molecules induces the mutual interaction between H2O and pendant groups of PTFE affecting ion transport by lowering the energy needed to overcome the potential barriers experienced by the protons.