Poly(o-anisidine) coatings on copper: synthesis, characterization and evaluation of corrosion protection performance

The poly(o-anisidine) (POA) coatings were synthesized on copper (Cu) by electrochemical polymerization (ECP) of o-anisidine (OA) and their corrosion protection performance in an aqueous solution of 3% NaCl was investigated by potentiodynamic polarization technique. The ECP of OA was carried out under cyclic voltammetric conditions from an aqueous solution of sodium oxalate to generate strongly adherent and smooth POA coatings on Cu substrates. These coatings were characterized by cyclic voltammetry (CV), UV-vis absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements. The optical absorption spectroscopy study reveals the formation of the mixed phase of pernigraniline base (PB) and emeraldine salt (ES) form of POA. The potentiodynamic polarization curves were used to evaluate the ability of the POA coatings to protect the Cu surface. The potentiodynamic polarization curves show that the POA coating increases the corrosion potential and drastically reduces the corrosion rate of copper. The corrosion rate of POA coated Cu is ∼100 times lower than that observed for bare Cu