Dynamic Colloidal Stabilization by Nanoparticle Halos

TL;DR

This paper investigates how nanoparticle halos can stabilize colloids through soft repulsive interactions, revealing conditions for stabilization and re-entrant attraction using integral equation methods.

Contribution

It provides a systematic analysis of nanoparticle halo effects on colloid stability, highlighting the balance between repulsion and attraction.

Findings

Optimal nanoparticle density leads to maximum repulsive barrier.

Excess nanoparticles cause re-entrant attraction and bridging effects.

Integral equation techniques effectively model colloid-nanoparticle interactions.

Abstract

We explore the conditions under which colloids can be stabilized by the addition of smaller particles. The largest repulsive barriers between colloids occur when the added particles repel each other with soft interactions, leading to an accumulation near the colloid surfaces. At lower densities these layers of mobile particles (nanoparticle halos) result in stabilization, but when too many are added, the interactions become attractive again. We systematically study these effects --accumulation repulsion, re-entrant attraction, and bridging -- by accurate integral equation techniques.