Wetting and particle adsorption in nanoflows

Document Type

Article

Publication Date

1-1-2005

Abstract

Molecular dynamics simulations are used to study the behavior of closely fitting spherical and ellipsoidal particles moving through a fluid-filled cylinder at nanometer scales. The particle, the cylinder wall, and the fluid solvent are all treated as atomic systems, and special attention is given to the effects of varying the wetting properties of the fluid. Although the modification of the solid-fluid interaction leads to significant changes in the microstructure of the fluid, its transport properties are found to be the same as in bulk. Independently of the shape and the relative size of the particle, we find two distinct regimes as a function of the degree of wetting, with a sharp transition between them. In the case of a highly wetting suspending fluid, the particle moves through the cylinder with an average axial velocity in agreement with that obtained from the solution of the continuum Stokes equations. In contrast, in the case of less-wetting fluids, only the early time motion of the particle is consistent with continuum dynamics. At later times, the particle is eventually adsorbed onto the wall and subsequently executes an intermittent stick-slip motion. We show that van der Waals forces are the dominant contribution to the particle adsorption phenomenon and that depletion forces are weak enough to allow, in the highly wetting situation, an initially adsorbed particle to spontaneously desorb. © 2005 American Institute of Physics.

Identifier

19944430078 (Scopus)

Publication Title

Physics of Fluids

External Full Text Location

https://doi.org/10.1063/1.1815341

ISSN

10706631

First Page

18

Last Page

17102

Issue

1

Volume

17

Grant

DE-FG02-03ER46068

Fund Ref

U.S. Department of Energy

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