Conductivity Dependence of PEG Content in an Anhydrous Proton Conducting Sol−Gel Electrolyte

Abstract

Proton conducting electrolytes composed of mixtures of a MePEG n SO 3 H acid and a sol−gel based MePEG n polymer have been prepared. These solutions display anhydrous proton conductivity reaching a maximum value of 1.38 × 10 - 5 S/cm at 55 °C with a 1.32 M mixture of MePEG 16 SO 3 H dissolved in the MePEG 12 polymer. The molar equivalent conductivity of the MePEG n SO 3 H acid is correlated with the volume fraction of PEG present in the mixture. This result indicates that conductivity in these solutions of acid and polymer is a function of the PEG content strongly suggesting the presence of a Grotthus mechanism of conductivity. In addition, we show the lack of a dependence of ionic and equivalent conductivity on the size of the MePEG n SO 3 H acid, indicating little to no contribution to conductivity from the vehicle mechanism.