Alternating strings and clusters in suspensions of charged colloids

TL;DR

This paper investigates the formation of alternating strings and clusters in charged colloid suspensions, highlighting the role of many-body effects and charge regulation in structure formation.

Contribution

It introduces a binary cell model incorporating many-body and charge-regulation effects to explain structure formation in charged colloids.

Findings

Induced dipoles near charge-reversal states promote structure formation.

Structures form despite purely repulsive electrostatic interactions.

Charge regulation influences the effective interactions and resulting structures.

Abstract

We report the formation of alternating strings and clusters in a binary suspension of repulsive charged colloids with double layers larger than the particle size. Within a binary cell model we include many-body and charge-regulation effects under the assumption of a constant surface potential, and consider their repercussions on the two-particle interaction potential. We find that the formation of induced dipoles close to a charge-reversed state may explain the formation of these structures. Finally, we will touch upon the formation of dumbbells and small clusters in a one-component system, where the effective electrostatic interaction is always repulsive.