Modeling and Simulation of Microscale Bipolar Particle Dynamics in an Applied Electric Field

The colloidal dynamics of bipolar microparticles is of growing theoretical interest in understanding and advancement of electrorheology and ferroelectric research. In this paper we present an interface resolved numerical study to analyze dynamics of ellipsoidal bipolar microparticles for various initial configurations. The bipolarity is imposed by providing surface charges of opposite polarity at the two ends of ellipsoidal particles. The numerical simulations show that in the absence of an external electric field, ellipsoidal particles form a head-to-tail chain or stay apart from each other depending on the inter-particle distance, as well as the magnitude and direction of the inherent polar moment. On the other hand, in presence of an external electric field, the assembly or clustering mechanism primarily depends on the magnitude and direction of the applied electric field. Simulation results also show that the electrorotation process is a function of initial configuration. This comprehensive numerical study will help to better understand the mechanisms of clustering, string formation, and the disaggregation of bipolar microparticles.