Electropolymerized coatings of polyaniline on copper by using the galvanostatic method and their corrosion protection performance in HCl medium

Abstract

The synthesis of polyaniline coatings on the copper (Cu) surface has been investigated by using the galvanostatic method. The synthesized coatings were characterized by Fourier transform infrared spectroscopy, UV–visible absorption spectrometry and scanning electron microscopy. The anticorrosion performances of polyaniline coatings were investigated in 0.5 M HCl medium by the potentiodynamic polarization technique and electrochemical impedance spectroscopy. The corrosion rate of polyaniline-coated Cu was found to be ∼27 times lower than bare Cu, and potential corrosion increased from −0.21 V versus Ag/AgCl for uncoated Cu to −0.19 V versus Ag/AgCl for polyaniline-coated Cu electrodes. Electrochemical measurements indicate that polyaniline coating has good inhibiting properties with a mean efficiency of ~96% at 10 mAcm−2 current density applied on Cu corrosion in acid media. The results of this study clearly ascertain that the polyaniline has an outstanding potential to protect Cu against corrosion in an acidic environment.