Electric-field induced capillary interaction of charged particles at a polar interface

TL;DR

This paper investigates how electric fields influence the capillary interactions between charged particles at polar interfaces, revealing a repulsive force that decays with distance and clarifying its role in particle behavior.

Contribution

It provides a theoretical analysis of electric-field induced capillary interactions, showing they are repulsive and decay as ^{-6}, and explains their non-involvement in secondary minima formation.

Findings

Capillary interaction decays as ^{-6} with particle separation.

Electrostatic pressure causes interface deformation with algebraic tail ^{-4}.

Electric-field induced forces are repulsive and not responsible for secondary minima.

Abstract

We study the electric-field induced capillary interaction of charged particles at a polar interface. The algebraic tails of the electrostatic pressure of each charge results in a deformation of the interface $u\sim \rho ^{-4}$. The resulting capillary interaction is repulsive and varies as $\rho ^{-6}$ with the particle distance. As a consequence, electric-field induced capillary forces cannot be at the origin of the secondary minimum observed recently for charged PMMA particles at on oil-water interface.