Berlin 2008 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 4: Colloidal Fluids
CPP 4.5: Vortrag
Montag, 25. Februar 2008, 15:45–16:00, C 264
Scaling laws in the rheology of colloidal dispersions — •David Hajnal1 and Matthias Fuchs2 — 1Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudinger Weg 7, D-55099 Mainz, Germany — 2Fachbereich Physik, Universität Konstanz, D-78457 Konstanz, Germany
We have analyzed the shear flow behavior of dense colloidal dispersions close to the glass transition in the framework of a schematic version of mode-coupling theory (MCT). The schematic model contains the universal aspects of MCT [1] and was successfully applied to describe experimental data for the flow behavior and the linear viscoelasticity of thermosensitive core-shell dispersions [2].
We have derived a universal analytic expression which describes the flow curves quantitatively for small shear rates. This analytic expression provides a deeper understanding of the shapes of the flow curves. For instance, the scaling of the yield stress, the zero-shear limit of the shear stress, and its singular behavior at the glass transition point can easily be obtained by studying special asymptotic limits.
[1] M. Fuchs and M. E. Cates, Schematic models for dynamic yielding of sheared colloidal glasses. Faraday Discuss. 123, 267-286 (2003).
[2] J. J. Crassous, M. Siebenbürger, M. Ballauf, M. Drechsler, D. Hajnal, O. Henrich and M. Fuchs, Shear stresses of colloidal dispersions at the glass transition in equilibrium and in flow. J. Chem. Phys., submitted.