Abstract

Poly (aniline-co-o-anisidine) of copolymer coating was synthesized on copper surface (Cu) in an aqueous solution containing 90 ml of 0.20 M NaOX + 10 ml of 0.20 M oxalic acid. The copper substrate in NaOX solution containing oxalic acid had a fairly reliable passive surface mainly due to the formation of copper (II) oxalate layer. The addition of oxalic acid to working electrolyte contributed to both the amount of copolymer deposition (growth) and that of copolymer coated per unit time of electropolymerization (growth rate). 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 oxalic acid led to the diminishing of the permeability of copolymer film. The copolymer coating exhibited an effective barrier property on copper electrode and provided a remarkable anodic protection to substrate for longer exposure time.