Three-body interactions in colloidal systems

TL;DR

This study directly measures three-body interactions in a colloidal system using laser tweezers and finds attractive forces, supported by nonlinear Poisson-Boltzmann calculations, advancing understanding of complex colloidal interactions.

Contribution

First direct experimental measurement of three-body interactions in colloids, combined with theoretical calculations to analyze microionic distributions.

Findings

Attractive three-body interactions observed

Agreement with nonlinear Poisson-Boltzmann calculations

Enhanced understanding of colloidal microionic environments

Abstract

We present the first direct measurement of three-body interactions in a colloidal system comprised of three charged colloidal particles. Two of the particles have been confined by means of a scanned laser tweezers to a line-shaped optical trap where they diffused due to thermal fluctuations. Upon the approach of a third particle, attractive three-body interactions have been observed. The results are in qualitative agreement with additionally performed nonlinear Poissson-Boltzmann calculations, which also allow us to investigate the microionic density distributions in the neighborhood of the interacting colloidal particles.