Electrodeposition of polypyrrole films on aluminum from tartrate aqueous solution

Abstract

The electrochemical synthesis of polypyrrole films on aluminum surfaces from aqueous solutions containing tartaric acid and pyrrole was performed using cyclic voltammetry and galvanostatic techniques. A mechanism that considers a porous aluminum oxide layer growing in parallel with the polymeric film explains the polypyrrole electrodeposition on aluminum surfaces. The more homogeneous the distribution of pores on the aluminum oxide layer, the smaller is the resistance offered to the polypyrrole film growth. Polypyrrole films deposited by cyclic voltammetry are much less uniform than those galvanostatically formed. Polymeric films galvanostatically deposited at higher current densities were more susceptible to overoxidation processes than those films formed at lower current densities, as demonstrated by FTIR analyses. Furthermore, films formed at low current density perform better on protecting aluminum surfaces against corrosion. ©2007 Sociedade Brasileira de Química.