Electrodeposition of polyaniline films on stainless steel and their voltammetric behavior in corrosive environments

Abstract

Polyaniline films were electrodeposited on the stainless steel substrates from aniline solutions with different acids. Kinetic of the film growth is discussed in terms of corrosion behavior of steel substrates in pure acids. Wide passive region in sulfuric and phosphoric acid enables initial oxidation of aniline and consequent deposition of polymer, without concurrent dissolution of alloy. On the other hand, in hydrochloric acid substrates actively dissolute at potentials necessary for aniline oxidation. However, formation of polymeric deposits is possible even in this case, probably due to the inhibition effect of aniline or oligoanilines formed during initial periods of anodic polarization. All deposited films exhibit electroactive behavior in low pH medium, while totally lose their ability for redox transitions in higher pH.