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.