PROTECTION OF COPPER CORROSION BY AN ULTRATHIN 2-DIMENSIONAL POLYMER FILM OF ALKANETHIOL MONOLAYER

An ultrathin (ca. 5.0 nm thick), closely packed (self-assembly), tight ly interconnected (two-dimensional polymer), and water-repellent (>130 degrees of the contact angle with water) film was prepared by modific ation of an 11-mercapto-1-undecanol self-assembled monolayer adsorbed on a copper surface with 1,2-bis(trichlorosilyl)ethane and subsequentl y with octadecyltrichlorosilane at 5 x 10(-4) M for 24 h. This film pr evented copper corrosion in aerated 0.5 M Na2SO4 with the protective e fficiency, P, of the film being maintained at over 95% in the solution for 15 h. The film provided excellent protection against indoor atmos pheric corrosion of copper for 300 days. Effects of the surface roughn ess on the water repellence of the surface covered with the film and o n the P value of an unmodified or modified alkanethiol monolayer were studied by using atomic force microscopy to examine mechanically abrad ed and electropolished copper surfaces.