Study on the Interaction of Rod-Shaped Particles in a Dc Uniform Electric Field

Abstract

The effect of secondary or localized dielectrophoresis (DEP) stemmed from the presence of particles plays an essential role in the particle chain and assembly under an externally applied uniform electric field. A great number of numerical studies have contributed to the particle-particle interaction. For the study, we solve the Laplacian and Navier-Stokes equations in finite element method to obtain the forces and torques for the freely suspended particle in terms of Maxwell stress and hydrodynamic stress tensors. For the simulations, the Arbitrary Lagrange-Euler (ALE) approach calculates the motion characteristics of rod-shaped particles in transient solution, including orientation and self-orientation angles, aspect ratio, and electric field strength. These results show that the DEP motion of both circle-rod and rod-rod particles depends significantly on their own initial position and angle. In particular, their major axes of rod-shaped particles have to align with the electric field, resulting in the distinct rotation due to the anisotropic electric polarization. In addition, the motion becomes further strengthened as the electric field magnitude, but the trajectories taken by them are not influenced so significantly by their set of the aspect ratio except for the orientation direction.

Keywords: Dielectrophoresis, DEP, Pearl chain, Rod-shaped particle interaction, Numerical simulation