Patterned self‐assembled alkanethiolate monolayers on gold. Patterning and imaging by means of scanning electrochemical microscopy

Abstract Electrochemically induced localized desorption of self‐assembled dodecylthiolate monolayers from a macroscopic Au electrode was performed using a scanning electrochemical microscope (SECM). The microelectrode of the SECM is operated as auxiliary electrode and moved in close proximity to the monolayer‐covered gold surface, thereby restricting electrochemical reactions occurring at the macroscopic gold surface to a region perpendicular beneath the auxiliary microelectrode. Subsequently, the obtained laterally‐structured monolayers have been imaged using the feedback mode of the SECM. High feedback currents occur over regions from which the alkanethiolate monolayer was locally desorbed while low currents are measured over the intact layer. The electrochemically induced desorption of alkanethiolate monolayers was laterally restricted to regions which are approximately 2–3 times larger in diameter than the diameter of the microelectrode used in the desorption step. The desorption protocol has been optimized to obtain renewed gold surfaces of defined geometry. First evidence was obtained that re‐adsorption of functionalized thiols onto these renewed and laterally structured gold surfaces, which are surrounded by the densely packed nonfunctionalized monolayer, may open routes for the fabrication of miniaturized integrated sensors and sensor arrays.