Ground state of a polydisperse electrorheological solid: Beyond the dipole approximation

TL;DR

This paper develops a simplified dipole-induced dipole model to analyze the ground state structures of polydisperse electrorheological fluids, revealing stability conditions and structural transitions beyond the dipole approximation.

Contribution

It introduces an analytic DID model for polydisperse ER fluids that extends previous dipole approximations, enabling easier simulations of complex structures.

Findings

Polydispersity can destabilize the body-centered tetragonal ground state.

The DID model agrees with multipole theory but is computationally simpler.

Dielectric contrasts significantly influence structure formation.

Abstract

The ground state of an electrorheological (ER) fluid has been studied based on our recently proposed dipole-induced dipole (DID) model. We obtained an analytic expression of the interaction between chains of particles which are of the same or different dielectric constants. The effects of dielectric constants on the structure formation in monodisperse and polydisperse electrorheological fluids are studied in a wide range of dielectric contrasts between the particles and the base fluid. Our results showed that the established body-centered tetragonal ground state in monodisperse ER fluids may become unstable due to a polydispersity in the particle dielectric constants. While our results agree with that of the fully multipole theory, the DID model is much simpler, which offers a basis for computer simulations in polydisperse ER fluids.