Electropolymerization of poly (aniline-co-o-anisidine) on copper and its anticorrosion properties

Abstract

Poly(aniline-co-o-anisidine) of copolymer coatings was synthesized on the copper surface (Cu) with two different amounts of p-toluenesulfonic acid (p-TSA) added to the aqueous sodium oxalate (NaOX) solution. The copper substrates in NaOX solutions containing p-TSA acid had a fairly reliable passive surface mainly due to the formation of copper (II) oxalate layer. The addition of p-TSA acid to the working electrolyte contributed to both the amount of copolymer deposition (growth) and that of copolymer coated per unit time of electropolymerization (growth rate). The growth of copolymer coating on Cu electrode was characterized by scanning electron microscopy. The corrosion performances of copolymer coatings were investigated in 3.5% NaCl solution with anodic polarization curves and electrochemical impedance spectroscopy. The results showed that p-TSA acid led to the diminishing of the permeability of the copolymer films. The copolymer coatings exhibited an effective barrier property on copper electrode and a remarkable anodic protection to substrate for longer exposure time.