The formation of a protective layer of 3-mercapto-propyl-trimethoxy-silane on copper

The formation of a protective layer of 3-mercapto-propyl-trimethoxy-silane (PropS-SH) on copper was studied by non-electrochemical (Quartz Crystal Microbalance, FTIR and XPS spectroscopy) and electrochemical (Impedance Spectroscopy, Potentiodynamic Polarization Curve recording) techniques.By simple immersion in the silanic bath (90/6/4 v/v methyl alcohol/water/silane solution), this agent immediately physisorbed on copper, but the protective effects were poor. Thiolate and siloxane bond formation improved the performances of the silanic layer. The process of curing formed a very efficient, scarcely porous, polymolecular layer, while the aging process formed a less corrosion-resistant, practically bidimensional layer.The effects of dipping and subsequent methanol rinsing on the protective performances of PropS-SH film were also determined.