Anti-corrosion effect of thiol self-assembled monolayers on Ag plate

With the high-rise of the cost of gold, more and more companies in the electronics industry are interested in using Ag to improve the contact conductivity by covering the copper connectors with a layer of Ag. But the inferior anti-corrosion property of Ag compared with gold is the biggest obstacles for its wide application. Three kinds of thiols (two alkane thiols:1-octanethiol and 1-dodecanethiol, and one heterocyclic thiol:2-mercaptobenzothiazol) are used here to form self-assembled monolayers (SAMs) on Ag plates to serve as anti-corrosion barrier. Reflectance and electrochemical data were obtained to confirm the Aganti-corrosion capability of the thiol SAMs. Microscope images of Ag surface before and after salt spray confirms the protection of the thiol SAM on Ag surface. The electrochemical cyclic voltammetry data shows that the defects level of 1-dodecanethiol SAM is the lowest among the three thiols for protecting Ag surface. Since the appearance is determined by both the illumination and reflectance of objects, the reflectance data of Ag plates with alkane thiol SAM was obtained to confirm that SAM does not affect the appearance on Ag plate. The reflectance of Ag plates after salt spray for 9 days also confirmed the better performance of 1-dodecanethiol SAM.