AC-field-induced Polarization for Uncharged Colloids in Salt Solution: A Dissipative Particle Dynamics Simulation

TL;DR

This study uses mesoscopic simulations to analyze how uncharged spherical colloids in salt solutions respond to alternating electric fields, focusing on volume polarization and comparing results with classical theories.

Contribution

It introduces a detailed simulation approach for uncharged colloids under AC fields, highlighting volume polarization as a key mechanism and validating against classical theories.

Findings

Polarizability depends on AC frequency and salt concentration.

Simulation results agree with Maxwell-Wagner and electrokinetic theories.

Volume polarization dominates the response of uncharged colloids.

Abstract

We study the response of a spherical colloid under alternating electric fields (AC-fields) by mesoscopic simulation method, accounting in full for hydrodynamic and electrostatic interactions. We focus on a special case of uncharged colloids. The main polarization mechanism is the "volume-polarization", where ionic currents are deflected by the core of the uncharged colloid. Specifically, we compute the polarizability of a single colloid and systematically investigate the effect of AC field frequency and salt concentration. The simulation results are compared with predictions from classical Maxwell-Wagner theory and electrokinetic theory.