Wetting and particle adsorption in nanoflows

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 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 Walls 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.

References in corpus (9)

• Liquid-vapor oscillations of water in hydrophobic nanopores
• Boundary conditions at a fluid - solid interface
• Influence of wetting properties on the hydrodynamic boundary condition at a fluid-solid interface
• Quantification of Order in the Lennard-Jones System
• Hard Spheres in Vesicles: Curvature-Induced Forces and Particle-Induced Curvature
• Screened hydrodynamic interaction in a narrow channel
• Molecular dynamics of flows in the Knudsen regime
• Adsorption phenomena in the transport of a colloidal particle through a nanochannel containing a partially wetting fluid
• Motion of grains, droplets, and bubbles in fluid-filled nano-pores

Cited by in corpus (7)

• Modelling approaches to the dewetting of evaporating thin films of nanoparticle suspensions
• Molecular simulation of translational and rotational diffusion of Janus nanoparticles at liquid interfaces
• Diffusion of a Janus nanoparticle in an explicit solvent: A molecular dynamics simulation study
• Parametric instability of the helical dynamo
• Hysteresis, force oscillations and non-equilibrium effects in the adhesion of spherical nanoparticles to atomically smooth surfaces
• Velocity Inversion in Nanochannel Flow
• Poiseuille flow past a nanoscale cylinder in a slit channel: Lubrication theory versus molecular dynamics analysis