(551c) Adsorption of Surfactants on Gold Nanoparticles Studied Via Molecular Simulations

Gold Nanoparticle (GNP) – surfactant interactions are important for numerous applications. While it is hypothesized that surfactants have preferential adsorption towards some GNP facets, there is lack of direct experimental and molecular simulation-based studies elucidating this phenomenon. Using metadynamics, we have identified regions on GNPs that are most favorable to surfactant adsorption. Furthermore, we have studied the adsorption behavior of surfactants on GNPs as a function of their alkyl tail length using umbrella sampling. Our results reveal that surfactants adsorb with their alkyl tails adsorbed on the GNPs surface. The adsorption free energy is favorable for the surfactant molecules with longer alkyl tails. It is most favorable for surfactants to adsorb in such a way that their polar head is on the edge of the GNPs facets.