Electrochemical synthesis and corrosion behavior of polyaniline-benzoate coating on copper

Electrochemical polymerization of polyaniline (PANI) coating on copper electrode was performed galvanostatically in the current density range between 0.50 and 1.25 mA cm(-2), from aqueous solution of 0.3 mol dm(-3) sodium benzoate and 0.2 mol dm(-3) aniline. The corrosion behavior of PANI coated copper and copper electrode exposed to 0.5 mol dm(-3) sodium chloride solution was investigated by potentiodynamic and electrochemical impedance spectroscopy techniques. It was observed that thin PANI (5 mu m) coating had provided efficient protection (similar to 96%) to copper in 0.5 mol dm(-3) sodium chloride solution. Unusual initial impedance behavior to that normally observed with conventional organic coatings was attributed to dedoping of benzoate anions from the polymer coating. (C) 2011 Elsevier B.V. All rights reserved.