Regensburg 2010 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 30: Posters II

DY 30.37: Poster

Donnerstag, 25. März 2010, 16:00–18:00, Poster C

Soret driven convection in a thermosensitive microgel suspension — •Jürgen Schmied¹, Stephan Messlinger¹, Wolfgang Schöpf¹, Ingo Rehberg¹, Miriam Siebenbürger², and Matthias Ballauf² — ¹Experimentalphysik V, Universität Bayreuth, 95440 Bayreuth — ²Institut für Physik, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin

We investigate thermal convection in a microgel suspension that consists of core-shell colloids which change their size with temperature. The swelling and shrinking of the particles dramatically modifies the effective volume of the gel fraction and therefore the viscosity of the suspension. In our experiment, we expose a Hele-Shaw convection cell to a constant temperature difference. Due to the relatively large Soret effect of the suspension, a gradient of the colloid concentration is induced, which strongly influences both the onset and the nonlinear behaviour of the thermal convection. The convection patterns are monitored via a shadowgraph setup and also via tracking of single fluorescent tracer particles. We report on the formation and evolution of convection patterns in this thermosensitive suspension.