Kinetics of desorption of alkanethiolates on gold.

Self-assembled monolayers (SAMs) of alkanethiols can undergo reductive desorption and oxidative re-adsorption. The Coulombic efficiency of the oxidative re-adsorption reaction is dependent on the chain length and solution pH. We show that the loss of alkanethiols from the surface after reductive desorption can be explained by a simple model that takes into account diffusion of the thiolate into the bulk solution at a rate that is determined by the bulk solubility. These results provide a quantitative basis for the determination of the loss of alkanethiols from the surface after reductive desorption.