Preparation of adherent films of poly-p-xylylenes on aluminum by electrolysis



The electrolysis of solutions of p-methylbenzyltrimethylammonium nitrate or, better, p-xylylenebis(trimethylammonium nitrate) or p-xylylenebis(triphenylphosphonium chloride or bromide) in a polar organic solvent with an aluminum cathode and a platinum anode results in the formation of adherent coatings of poly-p-xylylene on the cathode. The mechanism of this reaction involves the electrochemical generation of p-xylylene and its subsequent polymerization on the aluminum cathode. Competing reactions are formation of p-xylene and reduction of the solvent.