Regensburg 2010 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 25: Focus: Active Fluids

CPP 25.1: Hauptvortrag

Mittwoch, 24. März 2010, 09:30–10:00, H39

Designing small swimmers — •Ramin Golestanian — Department of Physics and Astronomy, University of Sheffield, Sheffield, UK

The directed propulsion of small scale objects in water is problematic because of the combination of low Reynolds number and strong thermal fluctuations at these length scales. One possibility for designing propulsion is to devise non-reciprocal deformation strategies that are simple enough to be realizable. This opens up the discussion of what is the minimum number of degrees of freedom that we can use in our design strategies for objects that can swim at low Reynolds numbers. We introduce a simple prototype of a model based on a linear assembly of three spheres that are attached by two flexible linkers that can change their lengths. We analyze the motion of this model swimmer both in the deterministic and stochastic regimes. Another strategy to achieve propulsion at low Reynolds numbers could be to take advantage of various phoretic phenomena. We propose a simple model for the reaction-driven propulsion of a small device is proposed as a model for a molecular swimmer in aqueous media. Finally, a number of experimental realizations of such microswimmers are discussed including, in particular, one experiment in Sheffield and another one in Barcelona.