Electrochemical and anti-corrosion properties of octadecanethiol and benzotriazole binary self-assembled monolayers on copper

•A kind of self-assembly monolayers containing C18H37-SH and BTA was prepared.•The self-assembly monolayers show high corrosion inhibition performance to copper.•There is a synergy between heterocycle and sulfydryl groups on corrosion inhibition.•The properties of the binary SAMs are related to assembling sequence.

Self-assembled monolayers based on octadecanethiol (C18H37-SH) and benzotriazole (BTA) (C18H37-SH&BTA SAMs) were fabricated on copper surface, showing effective corrosion protection for the substrate. The self-assembled monolayers (containing the composite SAMs and the SAMs based on single C18H37-SH or BTA) were characterized by surface enhanced Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and the results show that both C18H37-SH and BTA are successfully self-assembled on copper surface, forming compact SAMs. The anti-corrosion performance of the SAMs was studied by potentiodynamic polarization and electrochemical impedance spectroscopy. It is revealed that the anti-corrosion performance of the binary (C18H37-SH and BTA) composite SAMs is influenced by the assembling sequence. The C18H37-SH&BTA SAMs display the best anti-corrosion performance for copper with the highest charge transfer resistance of 5.0·105 Ω cm2.

Graphical abstractSelf-assembled monolayers (SAMs) were fabricated on copper surface by immersing copper specimens in the aqueous solution containing octadecanethiol (C18H37-SH) and benzotriazole (BTA) only for five minutes, showing very good corrosion protection for copper.Download high-res image (106KB)Download full-size image