Mesoscopic electrohydrodynamic simulations of binary colloidal suspensions

TL;DR

This paper introduces a comprehensive mesoscopic simulation model combining lattice Boltzmann, Nernst-Planck, and colloid boundary conditions to study electrokinetic phenomena in binary colloidal suspensions.

Contribution

It presents the first integrated simulation framework for electrohydrodynamics, combining fluid flow, ion transport, and colloid dynamics in a unified model.

Findings

Validated against analytic solutions for ionic distributions and droplet deformations.

Simulated colloidal behaviors at fluid interfaces, including breakup and electrophoretic mobility.

Demonstrated the model's capability to explore complex colloidal electrokinetic phenomena.

Abstract

A model is presented for the solution of electrokinetic phenomena of colloidal suspensions in fluid mixtures. We solve the discrete Boltzmann equation with a BGK collision operator using the lattice Boltzmann method to simulate binary fluid flows. Solvent-solvent and solvent-solute interactions are implemented using a pseudopotential model. The Nernst-Planck equation, describing the kinetics of dissolved ion species, is solved using a finite difference discretization based on the link-flux method. The colloids are resolved on the lattice and coupled to the hydrodynamics and electrokinetics through appropriate boundary conditions. We present the first full integration of these three elements. The model is validated by comparing with known analytic solutions of ionic distributions at fluid interfaces, dielectric droplet deformations and the electrophoretic mobility of colloidal suspensions. Its possibilities are explored by considering various physical systems, such as breakup of charged and neutral droplets and colloidal dynamics at either planar or spherical fluid interfaces.