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Effect of many-body interactions on the solid-liquid phase-behavior of charge-stabilized colloidal suspensions

J. Dobnikar·R. Rzehak·H. H. von Gruenberg
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Abstract

The solid-liquid phase-diagram of charge-stabilized colloidal suspensions is calculated using a technique that combines a continuous Poisson-Boltzmann description for the microscopic electrolyte ions with a molecular-dynamics simulation for the macroionic colloidal spheres. While correlations between the microions are neglected in this approach, many-body interactions between the colloids are fully included. The solid-liquid transition is determined at a high colloid volume fraction where many-body interactions are expected to be strong. With a view to the Derjaguin-Landau-Verwey-Overbeek theory predicting that colloids interact via Yukawa pair-potentials, we compare our results with the phase diagram of a simple Yukawa liquid. Good agreement is found at high salt conditions, while at low ionic strength considerable deviations are observed. By calculating effective colloid-colloid pair-interactions it is demonstrated that these differences are due to many-body interactions. We suggest a density-dependent pair-potential in the form of a truncated Yukawa potential, and show that it offers a considerably improved description of the solid-liquid phase-behavior of concentrated colloidal suspensions.

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J. Dobnikar, R. Rzehak, H. H. von Gruenberg. 2002-09-06. Effect of many-body interactions on the solid-liquid phase-behavior of charge-stabilized colloidal suspensions. https://doi.org/10.1209/epl%2Fi2003-00142-5

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