Determination of inhibition effect of 4-(2-aminophenylthio)-5-(5-mercaptopentylthio) phthalonitrile self-assembled film on copper corrosion

4-(2-aminophenylthio)-5-(5-mercaptopentylthio)phthalonitrile (AMPN) monolayer was self-assembled on fresh copper surface to protective film against copper corrosion in chloride solution. Self-assembled monolayer (SAM) was obtained after etching with nitric acid at ambient temperature. The optimum conditions for formation of SAM were established using cyclic voltammetry. The optimum conditions are THF as solvent, 15 mM concentration of the organic molecule and an immersion period of 8 h. The AMPN SAM on copper surface was characterized by XPS, SEM, AFM and ATR-FTIR spectroscopy. Corrosion protection ability of AMPN SAM was evaluated in 3.5 % NaCl solution using impedance, linear polarization resistance and potentiodynamic polarization methods. While bare copper showed a polarization resistance (Rp) value of 1.536 k.cm2 in NaCl aqueous environment, the Rp value for SAM concentration of 15 mM covered copper surface is 121.3 k.cm2. The AMPN SAM on copper afforded corrosion inhibition efficiency of 66.4–98.7 % in NaCl solution in the concentration range studied. The SAM functions as a mixed type inhibitor. SAM film of AMPN is a good corrosion inhibitor for copper corrosion.