(654b) Toward a Better Understanding of Nanoassembly: Importance of Molecular Granularity on Colloidal Forces

Authors: 
Chun, J., Pacific Northwest National Laboratory
Mundy, C. J., Pacific Northwest National Laboratory
Schenter, G. K., Pacific Northwest National Laboratory
Li, D., Pacific Northwest National Lab
De Yoreo, J. J., Pacific Northwest National Laboratory
To obtain fundamental understanding of nanoassembly processes such oriented attachment (OA), an important mechanism of non-classical crystal growth, one would need an in-depth analysis of the coupling between colloidal interactions and molecular details owing to intrinsic length scales involved in the processes; a continuum-based Derjaguin-Landau-Verwey-Overbeek (DLVO) theory needs to be revised. Utilizing the spatial density response of a solvent to a surface combined with simple correlating schemes, we related the discrete nature of solvent to electrostatic and dispersion interactions. It was found that colloidal interactions are sensitive to the spatial variation of solvent density, demonstrating significant deviations in the interactions from the conventional formulation (e.g., with uniform solvent density). A comparison to force measurements from surface force apparatus (SFA) and atomic force microscopy (AFM)-based dynamic force spectroscopy (DFS) indicates that such molecular granularity of solvent response would be critical to capture a physical picture of the assembly.