A method that significantly improves the charge-transfer barrier properties of self-assembled n-alkanethiol films on polycrystalline copper is presented in this paper. Chemically-formed films were further modified electrochemically by repetitive potentiodynamic cycling in ethanolic solutions containing small quantities of n-alkanethiols. The polarization modulation infrared reflection absorption spectra (PM-IRRAS) of the electrochemically-modified thiol films showed an increase in their surface packing density and structure order in comparison to those which were chemically formed. The electrochemical impedance spectra (EIS) revealed that the ability of these films to maintain barrier properties upon exposure to corrosive environments depends directly on their chemical and structural properties, which also influenced the wettability of the surface. Electrochemically-modified thiol films offer superior charge-transfer barrier properties over chemically-formed films.

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An electrochemistry-based method for the formation of functionalized alkanethiol layers on a 316L stainless steel surface was developed. The method was efficient in forming a very stable, irreversibly-attached COOH-terminated (mercaptoundecanoic acid) surface layer. This layer was used as a 'linker' to immobilize the extracellular matrix protein fibronectin to the 316L stainless steel surface. Fibronectin was irreversibly attached to the surface and, unlike physisorbed fibronectin, resisted detachment more in aggressive 0.1 M NaOH under sonication. The fibronectin-modified 316L stainless steel surface was more biocompatible towards attachment of endothelial cells than a bare (unmodified) 316L stainless steel surface, yielding a 25% improvement in cell density.