Detecting short-chain thiol binding on CTAB-stabilised gold nanorods at single particle level

Abstract

Deeper understanding the binding of thiol molecules on CTAB-capped gold nanorods enables the rational tuning of colloidal interactions. In this study, I would like to present my last results on the adsorption of short thiol-containing molecules on gold nanorods. It is shown that plasmon peak broadening originated from the increasing chemical interface damping (CID) combined with the corresponding peak shift provide information on the ligand exchange process at the single particle level. Based on the findings, the accumulation of negatively charged 3-mercaptopropionic acid (MPA) is reduced compared to that of the positively charged cysteamine because of the interaction of the given thiol-ligand and the native CTAB layer. While cysteamine readily replaces CTAB, the adsorption of MPA leads to a self-limiting process.