AbstractCation exchange membranes are used as solid polymer electrolytes (SPE) for proton transport in special types of electrolysers and fuel cells. A good contact with the electrodes is necessary to achieve high efficiency. Therefore, surface treatment of the solid polymer electrolyte using a plasma etching process is investigated to create favourable conditions for the preparation of sufficient membrane electrocatalyst composites. Nafion® membranes are etched in a pulsed 27 MHz oxygen/argon plasma under different conditions. The adjustment of the plasma parameters determine the surface structure and properties of the membrane after the etching process.—With a view to coat membranes in future, a new coating technique for temperature sensitive substrates by means of an MOPECVD process is beeing developed. Platinum, ruthenium and tin organyls are decomposed in argon/hydrogen plasma to create metallic thin films. The plasma parameters RF‐power, pressure, electrode temperature and plasma gas mixture significantly affect the quality of metal films deposited using this technique. After the optimization of these parameters the production of films with conductivities corresponding to their bulk metals is now possible.