A fluctuating hydrodynamics approach to simulating polarizable colloids in explicit ion electrolyte solutions

Modeling of micron-scale dielectric colloids in electrolyte solutions is inherently a multi-scale problem that poses difficulties for frameworks like all-atom molecular dynamics due to the long timescales associated with colloidal motion in experiments. Taking from continuum fluctuating hydrodynamics, we present a method to simulate these systems where the electrostatic and hydrodynamic interactions of colloids and ions are explicitly resolved but the solvent remains implicit. This top-down coarse-graining of the solvent allows us to resolve micron-scale flows generated by the colloids as well as the nano-scale dynamics of ions. We demonstrate that the method can reach length- and time-scales accessible by experiments by presenting validation cases which look at polarizable colloids in AC electric fields and the dynamics of ions in the surrounding fluid.