Dresden 2009 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 38: POSTERS Micro- and Nanofluidics
CPP 38.1: Poster
Thursday, March 26, 2009, 17:00–19:30, P3
Colloids dragged through a polymer solution: Experiment, theory, and simulation — •Christof Gutsche1, Friedrich Kremer1, Matthias Krüger2, Markus Rauscher2, Rudolf Weeber3, and Jens Harting3 — 1Institut für Experimentalphysik I, Universität Leipzig, 04103 Leipzig, Germany — 2Max-Planck-Institut für Metallforschung, Heisenbergstr. 3, 70569 Stuttgart, Germany and Institut für Theoretische und Angewandte Physik, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany — 3Institut für Computerphysik, Universität Stuttgart, Pfaffenwaldring 27, 70569 Stuttgart, Germany
Complex fluids in general and colloid-polymer mixtures in particular are an ideal model system for studying the structure and phase behavior of multicomponent systems. We present optical tweezer based microrheological measurements of the drag force on colloids pulled through a solution of lambda-DNA used here as a monodisperse model polymer. The experiments show a drag force that is larger than expected from the Stokes formula and the independently measured viscosity of the DNA solution. We attribute this to the accumulation of DNA in front of the colloid and the reduced DNA density behind the colloid.
C.Gutsche, F. Kremer, M. Krüger, M. Rauscher, R. Weeber, J. Harting. J. Chem. Phys. 129, 084902 (2008)