Dielectric Controlled Self-assembly in Binary Colloidal Mixtures

Electrostatic interactions play a key role in many self-assembly processes, including colloidal aggregation. Prior simulation work has reported a rich variety of aggregates formed in simple binary suspensions of oppositely charged spherical colloids. However, dielectric effects, which are complicated to compute due to their many-body nature, are generally ignored in these studies. By employing a novel efficient method to handle the polarization charges via a combination of the method of images and the method of moments, we are able to examine the role of polarization in colloidal aggregation and crystallization in large-scale simulations. We systematically vary size ratio and relative permittivity, and determine the phase diagram, showing that dielectric effects qualitatively alter self-assembled structures.