3D Numerical Study of the Electrokinetic Motion of a Microparticle Adsorbed at a Horizontal Oil/Water Interface in an Infinite Domain

Abstract

This work builds a three-dimensional (3D) simulation model and studies the electrokinetic velocity of a microparticle adsorbed at a horizontal oil/water interface in an infinite domain. The effects of the interface zeta potentials, the electric field, the oil dynamic viscosity, and the contact angle between the particle and the oil/water interface are investigated in detail. The results show that in an infinite oil/water interface system, both the negatively charged mobile oil/water interface and the negatively charged particle adsorbed to it move toward the positive electrode of the DC electric field, and the particle velocity increases along with the contact angle, the electric field strength, and the absolute values of negative zeta potential of both the particle and the oil/water interface. When the oil/water interface is positively charged with a relatively small zeta potential, the negatively charged microparticle also moves in the opposite direction of the electric field. The larger the oil dynamic viscosity, the smaller the electrokinetic velocity of the microparticle at the interface. Additionally, the numerical simulation results are compared with the reported experiment results under the same conditions, and they have good agreement.