Screening of heterogeneous surfaces: charge renormalization of Janus particles

TL;DR

This paper develops a nonlinear ionic screening theory for heterogeneously charged spheres, extending charge renormalization to include multipolar modes and applying it to Janus particles with significant effects.

Contribution

It introduces a general mode-decomposition approach for charge renormalization on heterogeneously charged surfaces, applicable to various surface patterns including Janus particles.

Findings

Strong renormalization effects observed for all multipoles

Generalized charge renormalization scheme for heterogeneous surfaces

Applicable to a wide class of surface heterogeneities

Abstract

Nonlinear ionic screening theory for heterogeneously charged spheres is developed in terms of a mode-decomposition of the surface charge. A far-field analysis of the resulting electrostatic potential leads to a natural generalization of charge renormalization from purely monopolar to dipolar, quadropolar, etc., including mode-couplings. Our novel scheme is generally applicable to large classes of surface heterogeneities, and is explicitly applied here to Janus spheres with differently charged upper and lower hemispheres, revealing strong renormalization effects for all multipoles.