Formation and characterization of PEDOT-modified Nafion 117 membranes

Nafion 117 membranes were modified with a thin film of poly(3,4-ethylenedioxythiophene) (PEDOT) by a diffusion-controlled polymerization process using a two-compartment cell with the monomer EDOT on one side of the membrane and the oxidizing agent FeCl3 on the other side. The methanol permeability and ion conductivity of the composite PEDOT/Nafion membranes were measured as a function of temperature and polymerization time by DC and AC polarization measurements in four-electrode technique and permeation experiments in a diaphragm cell. These modified membranes have lower methanol permeability while maintaining adequate conductivity.