Electrolytically Formed Polyimide Films and Coatings

A process was developed for the electrophoretic deposition of polyamic acids onto metal electrodes and subsequent conversion to the corresponding polyimide. Polyamic acids were electrodeposited from colloidal dispersions of amine salts of the corresponding acids contained in a mixed organic solvent system. The tough, adherent, pin‐hole free coatings have excellent mechanical, physical, and thermal properties. Correlations of coating thickness with current density, bath composition, and electrodeposition time are discussed and a mechanism for polymer electrodeposition is postulated.