Stability of self-assembled monolayers of organothiol mono and bipode on copper in presence of another organothiol solution

The stability of alkanethiol self-assembled monolayers (SAMs) on metallic substrates is an important aspect for further application. Some studies point out the poor stability of this coating and the displacement of alkanethiol from the monolayer by immersion in another alkanethiol solution.The aim of this work consists in a comparative investigation of self-exchange of three organothiols: 11-perfluorobutyl-1-thiol-undecane (or RfSH), 2-dodecylpropane-1,3-dithiol (or R(SH)2) and n-decanedithiocarboxylic (or RS2H).The immersion of RS2H monolayer into RfSH solution (first approach) leads to the incorporation of thiol molecules into the defects of the initial SAMs followed by the displacement of RS2H molecules by RfSH. While for RfSH SAM in presence of R(SH)2 solution (second approach), longer time of immersion is required to observe the incorporation of dithiol molecules into the coating as well as the displacement of thiol molecules.