Nanoscale Reductive Desorption of Alkanethiol Self-Assembled Monolayers on Polycrystalline Gold Surfaces Using Scanning Electrochemical Microscopy

Controlled deposition and desorption of self-assembled thiol monolayers on gold surfaces enable precise surface engineering, leading to tailored surface functionalities crucial for a wide range of applications in surface science, nanotechnology, and biomedicine. This work describes the nanoscale electrochemical desorption of self-assembled monolayers (SAMs) of alkanethiols on gold surfaces. Employing scanning electrochemical cell microscopy, we investigate the substrate- and potential-dependent process of SAM desorption with a focus on the impact of alkanethiol chain length and underlying substrate crystallinity. Our study reveals significant insights into the desorption behavior of SAMs at the nanoscale, elucidating phenomena masked in bulk reductive desorption processes. Through controlled experiments on both annealed and unannealed gold foil electrodes, we explore the role of crystal facet composition and chain length in SAM desorption. The results highlight the influence of substrate properties on the desorption curves and the quantity of desorbed molecules. This work not only advances our understanding of SAM desorption mechanisms but also offers valuable implications for various scientific and technological endeavors, including surface science, nanotechnology, and sensor development.