Tuning colloid-interface interactions by salt partitioning

TL;DR

This paper demonstrates how salt partitioning and charge regulation can precisely tune colloid-interface interactions from attraction to repulsion, with implications for designing adjustable emulsions.

Contribution

It introduces a novel understanding of how salt partitioning and charge regulation influence colloid-interface interactions, bridging experimental observations and theoretical insights.

Findings

Interaction can be tuned from attractive to repulsive

Salt partitioning affects colloid charge regulation

Findings explain recent experimental results

Abstract

We show that the interaction of an oil-dispersed colloidal particle with an oil-water interface is highly tunable from attractive to repulsive, either by varying the sign of the colloidal charge via charge regulation, or by varying the difference in hydrophilicity between the dissolved cations and anions. In addition, we investigate the yet unexplored interplay between the self-regulated colloidal surface charge distribution with the planar double layer across the oil-water interface and the spherical one around the colloid. Our findings explain recent experiments and have direct relevance for tunable Pickering emulsions.