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DY: Fachverband Dynamik und Statistische Physik

DY 28: Pattern formation in colloidal and granular systems II

DY 28.7: Talk

Friday, March 27, 2009, 12:00–12:15, HÜL 386

Convection in thermosensitive colloidal suspensions — •Florian Winkel¹, Stephan Messlinger¹, Wolfgang Schöpf¹, Ingo Rehberg¹, Miriam Siebenbürger², and Matthias Ballauff² — ¹Experimentalphysik V, Universität Bayreuth, D-95440 Bayreuth, Germany — ²Physikalische Chemie I, Universität Bayreuth, D-95440 Bayreuth, Germany

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 volume fraction and therefore the viscosity of the suspension. As a consequence, a temperature gradient applied to the suspension also induces a gradient of the colloid concentration which strongly influences both the onset and the nonlinear behavior of thermal convection. In our experiment we expose a Hele-Shaw convection cell to a constant temperature difference. The thermal convection is monitored via a shadowgraph setup. We report on the formation and evolution of convection patterns in our microgel suspension.