Surface coverage can control the dispersibility of TiO2 and ZrO2 nanoparticles in hydrophobic solvents: Comparison of linear and branched ligands

Abstract

Nanoparticles (NPs) can exhibit some unique properties such as dispersibility when their surfaces are modified with ligands. Unlike aqueous solvent systems, which can be described by conventional models, effective models that can describe the dispersibility of NPs in nonaqueous solvents are still controversial. In this study, phosphonate-modified metal oxide NPs were synthesized as a platform for a detailed investigation of how the ligand structure and surface coverage affect their dispersibility in hydrophobic solvents. Branched ligands were found to be more effective at reducing the saturated surface coverage than linear ligands. When the surface coverage was varied, the dispersibility of the NPs was different for the branched and linear structures, which highlights that the branched structure, an entropic ligand, provides higher dispersibility. The results contribute to further understanding of NP dispersibility in hydrophobic solvents.