Comparison of the protective effect of aromatic thiols adsorbed on copper

Stability and protection of copper from atmospheric oxidation, by aromatic thiolate adlayers obtained by adsorption of benzenethiol and 2-naphthalenthiol from solution, has been investigated by XPS. The adsorbed molecules do not show sulfur oxidation in air and in acid solution. Both the studied molecules clearly protect the copper surface from oxidation, reducing oxide and hydroxide formation in a similar way, despite differences in the structure. The trend of the O/Cu ratio and the stability of the thiolate adlayers are indicative of oxidation at defects of the self-assembled monolayers where the copper surface is not well protected. Copyright © 2010 John Wiley & Sons, Ltd.