Electrodeposition of poly(o-anisidine) coatings onto copper

Uniform and strongly adherent poly(o-anisidine) (POA) coatings have been successfully electrodeposited onto copper (Cu) substrates from the aqueous bath containing sodium oxalate and o-anisidine by using cyclic voltammetry (CV). CV, UV visible absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements were used to characterise these coatings, which indicates that the aqueous sodium oxalate solution is a suitable medium for the formation and deposition of POA onto Cu substrates. It is observed that the electrodeposition of POA coatings takes place after the passivation of the Cu substrate via formation of copper oxalate (CuC2O4.H2O) layer, which is confirmed by XRD measurement. The optical absorption spectroscopy study reveals the formation of the mixed phase of pernigraniline base (PB) and emeraldine salt (ES) forms of POA. The surface morphology of the coating is uniform, compact and featureless as revealed by SEM imaging.