Modeling the Behavior of Confined Colloidal Particles Under Shear Flow

TL;DR

This study models the behavior of confined colloidal particles under shear flow using molecular dynamics with hydrodynamic interactions, revealing layered structures and phase transitions dependent on shear and volume fraction.

Contribution

It introduces a combined MD and LB simulation approach to analyze layered colloidal behavior under shear, highlighting the role of particle exchange in phase transitions.

Findings

Layered structures form under shear with different densities and temperatures.

Particle exchange between layers is essential for disordering.

Phase diagram maps shear and volume fraction effects.

Abstract

We investigate the behavior of colloidal suspensions with different volume fractions confined between parallel walls under a range of steady shears. We model the particles using molecular dynamics (MD) with full hydrodynamic interactions implemented through the use of a lattice-Boltzmann (LB) fluid. A quasi-2d ordering occurs in systems characterized by a coexistence of coupled layers with different densities, order, and granular temperature. We present a phase diagram in terms of shear and volume fraction for each layer, and demonstrate that particle exchange between layers is required for entering the disordered phase.