Dresden 2009 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 5: Soft matter

DY 5.8: Talk

Monday, March 23, 2009, 16:30–16:45, ZEU 255

Structure and high-frequency viscosity in dispersions of charge-stabilized colloidal spheres — •Marco Heinen and Gerhard Nägele — Institut für Festkörperforschung, Teilinstitut Weiche Materie, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany

The short-time effective viscosity of suspensions of charge-stabilized colloidal spheres is calculated by means of a renormalized density fluctuation expansion. Systems at various volume fractions, particle charges and salt concentrations are considered.

The only input required for this calculation is the static structure factor which we obtain from appropriate Ornstein-Zernicke integral equation theories. In particular, we investigate a simple modification of the well-known rescaled mean spherical approximation (RMSA) suggested by Snook and Hayter, which includes a microionic background correction that tends to compensate the typical underestimation of microstructure by the RMSA. The background-corrected RMSA is in good agreement with our simulation data and the computationally more expensive Rogers-Young scheme.