Influence of oxygen and oxidant on corrosion inhibition of cysteine self-assembled membranes for copper

Self-assembled membranes (SAMs) of cysteine (Cys) were prepared on the copper surface under aeration, de-aeration, in the presence of 10–5 M KMnO4 and 10–5 M ascorbic acid, respectively. The corrosion inhibition of different Cys SAMs for copper in 3% NaCl solution was investigated by the electrochemical impedance spectroscopy and the polarization techniques. The results show that all Cys SAMs shift the corrosion potential toward more positive values. The presence of a small amount of KMnO4 gives the best protective effect of the Cys SAMs. The assembly mechanism of Cys SAMs is discussed based on molecular dynamics method. The Cys is easier to adsorb onto the Cu2O surface to form a protective film.