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Self-diffusion coefficients of charged particles: Prediction of Nonlinear volume fraction dependence

M. Watzlawek·G. Naegele
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Abstract

We report on calculations of the translational and rotational short-time self-diffusion coefficients $D^t_s$ and $D^r_s$ for suspensions of charge-stabilized colloidal spheres. These diffusion coefficients are affected by electrostatic forces and many-body hydrodynamic interactions (HI). Our computations account for both two-body and three-body HI. For strongly charged particles, we predict interesting nonlinear scaling relations $D^t_s\propto 1-a_tϕ^{4/3}$ and $D^r_s\propto 1-a_rϕ^2$ depending on volume fraction $ϕ$, with essentially charge-independent parameters $a_t$ and $a_r$. These scaling relations are strikingly different from the corresponding results for hard spheres. Our numerical results can be explained using a model of effective hard spheres. Moreover, we perceptibly improve the known result for $D^t_s$ of hard sphere suspensions.

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M. Watzlawek, G. Naegele. 1997-07-28. Self-diffusion coefficients of charged particles: Prediction of Nonlinear volume fraction dependence. https://doi.org/10.1103/physreve.56.1258

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