Regensburg 2010 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 30: Posters II
DY 30.37: Poster
Thursday, March 25, 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.