FILMFORMING ELECTROPOLYMERIZATION OF PYRROLE ON IRON IN AQUEOUS OXALIC-ACID

Electrodeposition of polypyrrole on iron from aqueous solutions of pyr role and oxalic acid yields strongly adherent, smooth polymer layers. The electrochemical process proceeds at a constant current density of 2mA cm(-2). The potential-time curve is characterized by a short induc tion period, where active iron dissolution occurs. The perfect perform ance of the polymer coating is attributed to the formation of an iron( II) oxalate interlayer. The influence of current density, pyrrole conc entration and KNO3 addition on the electrodeposition process and the e lectrochemical and physical properties of the layers are studied in de tail.