Microtribological and corrosion behaviors of 1H,1H,2H,2H-perfluorodecanethiol self-assembled films on copper surfaces

Fluoroorganic monolayers adsorped on copper are studied in terms of organization, structure, electrochemical behavior, corrosion and tribological properties. 1H,1H,2H,2H-perfluorodecanethiol thin films are grafted on copper via a self-assembling process. PM-IRRAS and XPS were used to investigate the organization, composition and structural properties of the SAMs. Cyclic voltammetry studies revealed a good oxidation blocking factor and polarization curves showed good anti-corrosion properties for the fluoroorganic film. However, these properties were inferior to those of n-dodecanethiol based SAMs. This was accounted for by the lower packing density and the larger number of defects of the 1H,1H,2H,2H-perfluorodecanethiol SAMs probably due to electrostatic and steric repulsion between fluorine atoms along the carbon chain and a number of CH2 groups insufficient to permit good organization. Fluorine groups present in the monolayer of the fluoroorganic SAMs led to excellent lubricant properties for the ultrathin film. Surface wear resistance was also improved thanks to SAM grafting. 1H,1H,2H,2H-perfluorodecanethiol SAMs thus appear to be very interesting lubricants for copper as they improve surface mechanical properties by diminishing surface friction and wear. (C) 2010 Elsevier B.V. All rights reserved.