Berlin 2008 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 32: Colloid Dynamics

CPP 32.1: Vortrag

Donnerstag, 28. Februar 2008, 11:15–11:30, C 264

Directed motion of colloidal particles by external magnetic fields — •Christian Kreidler, Larysa Baraban, Ina Seuffert, Paul Leiderer, and Artur Erbe — Universität Konstanz. FB Physik, Germany

Directed motion of microscopic particles can be used in many biological systems to transport molecules in a controlled way. Existing techniques, e.g. laser tweezers, work well under certain conditions. Here we demonstrate a concept of micro engines, which is based on the usage of asymmetrically catalytic colloidal particles. A chemical reaction is used to generate movement of the magnetic particles in suspension. Specially designed magnetic properties of colloids help to achieve their directed motion on the long time scale. The strength of the external magnetic field influences the velocity of the particles. Increasing its amplitude we can change the direction of the motion from antiparallel to parallel to the magnetic field. In principle, the technique can work even without direct optical access to the system. We present the time dependence of the mean square displacement for these particles as a proof of our concept. Further experiments concentrate on binding biological material to the moving particles in order to demonstrate the ability of the particles to serve as "transporters" for molecules.