Coupling between long-range colloidal forces and short-range molecular details for better understanding of nanocrystal assembly

Nanocrystal assemblies such oriented attachment (OA) unavoidably involve chemical physics at different length scales. As a result, the coupling between colloidal forces and molecular details would become critical to gain physical insights on nanocrystal assemblies. We used simple schemes to correlate the discrete nature of solvent (i.e., molecular details) to electrostatic and dispersion forces (i.e., colloidal forces) based on the spatial density response of a solvent at solid-liquid interfaces. Colloidal forces are shown to be sensitive to the spatial variation of solvent density, demonstrating appreciable deviations in the interactions from the conventional approach such as Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Such “molecular granularity” concept can be also used to provide important insights on understanding of forces between mineral surfaces obtained from atomic force microscopy (AFM)-based dynamic force spectroscopy (DFS)