Study of the protection performance of self-assembled monolayers on copper with the scanning electrochemical microscope

• The pitting process of Cu in NaCl solution is observed in situ.
• Degradation of the assembly film is detected by scanning electrochemical microscope.
• The assembly method decreases the interaction between organic molecules and the tip.
• The proportion of Cu(I) is crucial to the stability of the self-assembled film.

The protection performance of self-assembled monolayers (SAMs) formed by 2-(Pyridin-2-yliminomethyl)-phenol (HL) on the surface of copper has been studied in situ with the scanning electrochemical microscope (SECM). The pitting dynamic processes were observed in sodium chloride solution without the presence of SAMs, but they tended to be inhibited by SAMs if the assembly time was long enough. During the scanning process, the self-assembled method decreases the interaction between the HL molecules and the SECM tip greatly.