On the Way to the Location-Selective Replacement of Self-Assembled Monolayers: An Electrochemical Approach

Abstract Location-selective engineering of chemically identical areas of a complex substrate by the deposition of several different self-assembled monolayers (SAMs) represents a challenge of interfacial nanotechnology. These areas cannot be distinguished by tailoring the anchoring group of the different SAM-forming molecules, since this group, dictated by surface chemistry, should be the same for all these molecules. However, as shown in the present study, such engineering can be potentially performed electrochemically, by the successive assembly of one of the SAMs on all the areas, its controlled removal from selected areas by applying a system-specific reductive desorption potential, and the deposition of the second SAM onto these areas, while the first SAM is preserved in all other regions. The approach was tested with individual samples and several aromatic SAM-forming molecules with either thiolate or selenolate anchoring to the substrate (Au). It worked well for most combinations of these molecules, which provides a reliable basis for its extension to real-life heterogeneous templates, such as circuit boards hosting different types of organic transistors, requiring type-specific interface engineering.