Brownian dynamics simulation of chain formation in electrorheological fluids

Brownian dynamics (BD) simulations based on a novel Langevin integrator algorithm are used to simulate the dynamics of chain formation in electrorheological (ER) fluids that are non-conducting solid particles suspended in a liquid that has a dielectric constant different from that of the ER particles. An external electric field induces polarization charge distributions on the spheres' surfaces that can be modeled as point dipoles in the centers of the spheres. The interaction of these aligned dipoles leads to formation of chains and other aggregates in the ER fluid. In this work, we introduce our methodology and report results for various quantities characterizing the structure of the ER system as obtained with BD simulations. These quantities include the potential energy, diffusion constant, average chain length, chain length distributions, and pair correlation functions. Their behavior as a function of time is presented as the electric field is switched on. The properties of the ER fluid change considerably making this system a potential basic material of many applications.