Substitution of one self-assembled monolayer (SAM) with another was difficult to complete using traditional self-assembly techniques. However, this process could be conveniently accomplished by electrochemically directed desorption-adsorption approach, in which the potentials of the substrate were controlled to strip or to form SAMs. By usage of substrates with two Au areas insulated from each other, 4-aminothiophenol (ATP) and n-dodecanethiol (DDT) SAMs were prepared separately on different areas via electrochemical substitution assembly. Cyclic voltammetry showed that the electrochemical features were quite different at ATP and DDT coated areas, though these two areas were closely located. In addition, area-selective self-assembled monolayer of Au nanoparticles was successfully prepared on the substrates coated with different SAMs.

Key words: self-assembled monolayer (SAM), electrochemical substitution assembly, gold nanoparticle, n-dodecanethiol, 4-aminothiophenol