Short-time rotational diffusion in monodisperse charge-stabilized colloidal suspensions

TL;DR

This study examines how electrostatic and hydrodynamic interactions affect the short-time rotational self-diffusion in charge-stabilized colloidal suspensions, revealing that electrostatic effects reduce hydrodynamic influence and that salt-free systems follow a quadratic volume fraction dependence.

Contribution

It provides a detailed analysis of the combined effects of electrostatic and hydrodynamic interactions on rotational diffusion, introducing an effective hard sphere model for salt-free suspensions.

Findings

Hydrodynamic interactions are less influential for charged particles.

Salt-free suspensions show a quadratic volume fraction dependence.

Electrostatic interactions modify the impact of hydrodynamic effects.

Abstract

We investigate the combined effects of electrostatic interactions and hydrodynamic interactions on the short-time rotational self-diffusion coefficient in charge-stabilized suspensions. We calculate this coefficient as a function of volume fraction for various effective particle charges and amounts of added electrolyte. The influence of the hydrodynamic interactions on the rotational diffusion coefficient is less pronounced for charged particles than for uncharged ones. Salt-free suspensions are weakly influenced by hydrodynamic interactions. For these strongly correlated systems we obtain a quadratic volume fraction-dependence of the diffusion coefficient, which is well explained in terms of an effective hard sphere model.