Investigation of two-component mixed self-assembled monolayers on gold

Abstract

Two-component mixed self-assembled monolayers (SAMs) composed of 2-mercapto-5-methyl-1,3,4-oxadiazole (MMO) and 1-dodecanethiol (C 12 SH) in various molar percentages were prepared on gold surfaces by self-assembly. X-ray photoelectron spectroscopy (XPS) and wettability results gave evidence that the coverage of MMO was controlled by the composition of MMO in the assembling solution. The monolayer coverage and apparent rate constant of the redox active probes in solution of different molar ratios of mixed SAMs could be calculated using impedance measurements. The cyclic voltammetry reveals that the probes are selectively passed through the mixed SAMs depending upon their properties.Key words: self-assembled monolayers (SAMs), X-ray photoelectron spectroscopy (XPS), electrochemistry, electrochemical impedance analysis.