Role of Solvents in Oriented Attachment of Ag Nanoparticles: Insights from Molecular Dynamics Simulations and Topological Analysis

Although the solvation force is considered one of the key forces behind the oriented attachment (OA), the precise roles of solvents in this process remain incompletely elucidated. In this study, we examined the effect of solvent polarities (water, acetone, and chloroform) on the attachment of silver nanoparticles by calculating the free energy curves for the OA process. The observed magnitudes of the binding energies and approaching and dissociation energy barriers are commensurate with the respective solvent polarities. Consequently, OA is more likely to occur in acetone with an intermediate permittivity relative to that of water and chloroform. Additionally, we identified a topological descriptor, namely, the Euler characteristic, of the solvent network, especially the water network, between two approaching surfaces, which manifests a linear correlation with the observed free energy profiles. This descriptor holds promise as a quantitative tool for predicting interactions between nanoparticles in solvent environments featuring hydrogen bond networks.