Aspects of polyaniline electrodeposition on aluminium

Abstract

Electrodeposition of polyaniline (PAni) from acid solutions on spontaneous passivating electrodes such as Al is not so obvious as on active metals (Fe and Ni). The methods that can result in deposition are: (1) surface pre-treatment with a chelating agent (alizarin) to block the hydrogen evolution reaction on aluminium and (2) a suitable monomer concentration (critical monomer concentration) to decrease the polymerisation induction time. The oxidation of aluminium to thick porous film limits the growth kinetics of PAni during deposition by cyclic voltammetry. We found that after reducing hydrogen evolution by surface chelation, for film growing in 0.5 M H2SO4 a concentration of 0.4 M aniline is required.