Electrochemical formation of a polyaniline-analogue monolayer on a gold electrode

Electrochemical preparation of polymerized self-assembled monolayers on an Au(111) substrate has been attempted by using aminobenzenethiol and 3-aminophenethylthiol. A self-assembled monolayer of aminobenzenethiol was easily polymerized if it consisted of ortho and meta isomers in their molar ratio of 1:1 but not at a single component monolayer of each isomer. In contrast, a self-assembled monolayer of a single component of 3-aminophenethylthiol allowed its easy electrochemical polymerization. The polymerized monolayers gave electrochemical activities very similar to those of conventional polyaniline and its derivatives. Furthermore, the self-assembled monolayer of these thiols got high stability against reductive desorption in an alkaline solution when polymerized. Underpotential deposition of Cu gave Cu coverage of 41% and 65% on the electrodes coated with the polymerized monolayers of aminobenzenethiol and 3-aminophenethylthiol, respectively.