Münster 1999 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 41: POSTER II

DY 41.56: Poster

Donnerstag, 25. März 1999, 09:30–13:00, Z

Long-Time Diffusion and Linear Viscoelasticity of Colloidal Suspensions — •Adolfo Javier Banchio¹, Johan Bergenholtz², Gerhard Nägele¹, and Rudolf Klein¹ — ¹Fakultät für Physik, Universität Konstanz, Postfach 5560, D-78457 Konstanz — ²Department of Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA

The long-time dynamics and linear viscoelastic properties of hard sphere and charge-stabilized suspensions are calculated from a recently developed mode coupling theory (MCT) [1]. Results are presented for the long-time self- and collective diffusion coefficients, the shear stress autocorrelation function, and the frequency-dependent viscosity. The MCT predictions for linear viscoelasticity are shown to be in excellent accord with experimental data on concentrated hard sphere suspensions [2]. Moreover, the stress autocorrelation function is shown to relax over a time scale inversely proportional to long-time diffusion. Two proposed generalizations of the Stokes-Einstein relation are examined using the MCT results. According to MCT, both relations work well for concentrated hard sphere suspensions, but deviations are found for charge-stabilized suspensions at low salinity.

[1] G. Nägele and J. Bergenholtz, J. Chem. Phys. 108, 9893 (1998).

[2] A. J. Banchio, J. Bergenholtz and G. Nägele, submitted to Phys. Rev. Lett. (1998).