Thermodynamic study of the reactivity of the two topological point defects present in mixed self-assembled monolayers on gold nanoparticles

A study was conducted to investigate the place-exchange at ligand-defined topological point defects in mixed-monolayer-protected nanoparticles (NP) and present a full thermodynamic analysis of reactivity at point defects in these self-assembled monolayers (SAM). The study demonstrated that the kinetics and free energy of the reactions are different at these points, when compared with clean or monolayer-protected gold surfaces. It was also demonstrated that these thermodynamic parameters are affected by the identity of the molecules in the ligand shell. It was observed that mixed SAMs, composed of a binary mixture of immiscible thiolated molecules phase-separated on flat surfaces, forming wormlike domains. The shape of the domains were determined by an equilibrium between enhthalpic losses and entropic gains associated with the formation of domain boundaries.