Nonnegligible Nano-confinement Effect on Solvent-mediated Interactions between Nanoparticles

Abstract Separating nanoparticles (NPs) by means of microfluidics represents a promising method. One of the associate challenges is how to regulate the interactions between NPs in confined solvents for avoiding particle aggregation. To tackle this challenge, herein we conduct a theoretical study to interpret the confinement effects on the potential of mean force between two NPs in nanochannels. By using the classical density functional theory, the effects of pore width, wall wettability, NP size, and solvent-NP interactions are unraveled. It is found that the nano-confinement can noticeably enhance the short-ranged attraction between NPs, and the attraction strength can be moderated by enlarging pore size, making wall solvophobic, shrinking NP size, and widening the range of solvent-NP interaction. This study provides a theoretical guidance towards the development of efficient particle separation method in nanochannel-based devices.