# Surfactant Mediated Particle Aggregation in Nonpolar Solvent

## TL;DR

This study investigates how surfactant concentration affects particle aggregation in nonpolar solvents, revealing a non-monotonic stability behavior explained by DLVO theory and measured surface charges.

## Contribution

It provides a quantitative analysis of particle stability in nonpolar media using time-resolved light scattering and DLVO theory, highlighting the role of surfactant concentration.

## Key findings

- Low surfactant concentrations lead to weakly charged, unstable suspensions.
- Intermediate concentrations increase stability due to higher particle charge.
- High surfactant levels neutralize particles, causing rapid aggregation.

## Abstract

Aggregation behavior of particles in nonpolar medium is studied with time-resolved light scattering. At low concentrations of surfactant particles are weakly charged and suspensions are not stable. Suspensions get progressively more stable with increasing surfactant concentration as particles get more highly charged. At high concentrations the particles get neutralized and aggregation is again fast. The theory of Derjaguin, Landau, Verwey, and Overbeek (DLVO) is able to predict the stability ratios quantitatively by using the experimentally measured surface charge, screening lengths and van der Waals forces.