Influence of particle-wall electrostatic interactions on packing of charged micron particles.

Abstract

Packing of charged micron-sized particles on surfaces is ubiquitous in both natural and industrial processes, where the packing structures critically determine system properties and performance. In practice, the materials of the surfaces can vary widely, giving rise to distinct particle-wall electrostatic interactions that drastically modulate the packing process. Therefore, we perform numerical simulations to study the packing of identically charged micron particles under different electric boundary conditions. We show that the maximum number of deposited particles is strongly influenced by particle-wall interactions, governed by the competition between incident particle kinetic energy and the repulsion from previously deposited particles. Furthermore, the resulting packing structures differ qualitatively: looser packings form near noninteracting or dielectric walls, whereas conducting walls yield much denser configurations. By quantifying energy changes induced by both deposited particles and other incoming particles, we identify two competing electrostatic mechanisms and derive an effective adhesion parameter that captures these effects in a unified framework. Our results highlight the critical role of particle-wall electrostatic interactions in predicting and controlling the packing behavior of charged particles.