8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Tue 611:23-14:00P9.69Enhanced shear separation for chiral magnetic colloidalaggregatesFabrice Thalmann, 1 Carlos Mendoza, 2 and Carlos M. Marques 11 Institut Charles Sadron, CNRS, UdS, 23 rue du Loess, BP 84047 67034, Strasbourg,France2 Instituto de Investigaciones en Materiales, UNaM, Mexico, MexicoWe study theoretically the designing principles of the simplest colloidal propeller, an architecturebuilt from four identical spheres that can couple translation with rotation to produce controlleddrift motion. By considering superparamagnetic beads, we show that the simultaneous action of amagnetic field and a shear flow leads to the migration of the cluster in the vorticity direction. Weinvestigate the dependence of the migration velocity on the geometrical parameters of the clusterand find that significant cluster separation can be achieved under the typical operation conditionsof microfluidic devices. Interestingly, we observe significant differences between shear separationand propeller efficiencies of a given aggregate.Phys. Rev. E 82, 060401(R) (2010)69