Control of Surface Tension at Liquid-Liquid Interfaces Using Nanoparticles and Nanoparticle-Protein Complexes

Subtle changes in the monolayer structure of nanoparticles (NPs) influence the interfacial behavior of both NPs and NP-protein conjugates. In this study, we use a series of monolayer-protected gold NPs to explore the role of particle hydrophobicity on their dynamic behavior at the toluene-water interface. Using dynamic surface tension measurements, we observed a linear decrease in the mesoequilibrium surface tension (gamma) and faster dynamics as the hydrophobicity of the ligands increases. Further modulation of gamma is observed for the corresponding NP-protein complexes at the charge-neutralization point.