A polymerization process is provided using a mixture of a solvent, a monomer, an oxidizing agent, and a moderator. The mixture is coated on a substrate and heated to initiate oxidative polymerization. At least one of three process conditions is used: the solvent having a boiling point in excess of about 120.degree. C.; the total concentration of the monomer, the oxidizing agent, and the moderator being at least about 40% by weight; and the molar concentration of the moderator being greater than the molar concentration of the monomer.