Monitoring the electrochemical transformation of an azobenzene-terminated alkanethiolate monolayer at gold by chemical force microscopy

Chemical Force Microscopy (CFM) was used to study the electrochemical behav ior of azobenzene-terminated self-assembled monolayers (SAMs). Both the gol d-coated AFM tip and the gold-coated silicon substrate were modified with a 4-((N-(2 '-mercapto-ethyl)-amino) carbonyl) azobenzene monolayer. For such a system, only when the reduction/oxidation reaction of azobenzene group o ccurs, the adhesion force between the tip and sample shows a drastic change , demonstrating the ability of CFM in monitoring the electrochemical transf ormation of an azobenzene group.