Plasma polymerized barrier films on membranes for direct methanol fuel cells

The methanol permeation through fuel cell relevant Nafion® membranes is investigated at different concentrations of methanol in aqueous solutions. Thin plasma polymerized barrier films are deposited on Nafion® membranes in a low pressure microwave generated plasma to reduce their methanol permeability. The methanol permeability was measured as a function of time using a gas chromatograph with a flame ionisation detector. It is shown that a plasma polymer layer with a thickness of approximately 0.27 μm on Nafion® membranes reduces the permeability to methanol by a factor of approximately 20.