Density-dependent interactions and structure of charged colloidal dispersions in the weak screening regime

TL;DR

This study investigates the structure of charge-stabilized colloidal suspensions at low ionic strength, revealing a non-monotonic density dependence of effective charge and interaction energy through experiments and simulations.

Contribution

It provides new insights into the density-dependent behavior of colloidal interactions in weak screening regimes using combined experimental and simulation approaches.

Findings

Non-monotonic density dependence of effective charge observed.

Structural behavior consistent with primitive model simulations.

Experimental results extend understanding of colloidal interactions at low ionic strength.

Abstract

We determine the structure of charge-stabilized colloidal suspensions at low ionic strength over an extended range of particle volume fractions using a combination of light and small angle neutron scattering experiments. The variation of the structure factor with concentration is analyzed within a one-component model of a colloidal suspension. We show that the observed structural behavior corresponds to a non-monotonic density dependence of the colloid effective charge and the mean interparticle interaction energy. Our findings are corroborated by similar observations from primitive model computer simulations of salt-free colloidal suspensions.