Regensburg 2010 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 1: Topical Session Glass Dynamics I

MM 1.1: Topical Talk

Montag, 22. März 2010, 10:15–10:45, H16

Colloidal Liquids and Glasses under Shear — •Stefan Egelhaaf — Condensed Matter Physics Laboratory, Heinrich-Heine-University, 40225 Düsseldorf, Germany

Colloidal liquids and glasses have been investigated experimentally. They consist of hard-sphere colloids with a short-range attraction induced by the depletion effect of non-adsorbing polymers, which allows us to control the range and strength of the particle-particle interactions. In these systems, liquid and crystalline states represent the equilibrium phases, while non-equilibrium, arrested states are observed at high colloid and/or polymer concentrations.

We have investigated the behaviour of these non-equilibrium states under shear. They were subjected to oscillatory shear as well as switch-on and switch-off of steady shear flow. The effect of shear on the structure and dynamics of the particles was determined. Due to their size, the particle motion can be followed using confocal microscopy and their dynamics quantified by, e.g., the mean-squared displacements. The transient dynamics show super-diffusive motion at intermediate times. These results are compared to recent simulations and theoretical predictions.