Plasma deposition of polymer electrolyte membrane for proton exchange membrane fuel cell (PEMFC) applications

Sulfonated 'Nafion-like' plasma polymerized membranes were synthesized by plasma polymerization of a mixture of styrene and trifluoromethane sulfonic acid monomers in a low-frequency after-glow capacitively coupled plasma (CCP) discharge reactor. The synthesized plasma polymerized membranes are flat and uniform with a few microns thickness. Their structure detected by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy is very rich with sulfonic acid groups (up to 3 at.%). The proton transport number and ion exchange capacity were investigated in details. The results are compared with that of a commercial available Nafion® 117.