Dresden 2014 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 39: Active Colloids
CPP 39.5: Vortrag
Donnerstag, 3. April 2014, 10:45–11:00, ZEU 260
Non-Gaussianity in suspensions of self-propelled Janus particles — •Borge ten Hagen1, Xu Zheng2, Andreas Kaiser1, Zhanhua Silber-Li2, and Hartmut Löwen1 — 1Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany — 2State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, CAS, Beijing 100190, People’s Republic of China
Spherical Janus particles are one of the most prominent examples for active Brownian objects. Here, we study the diffusiophoretic motion of such microswimmers in experiment and in theory. Three stages are identified: simple Brownian motion at short times, super-diffusion at intermediate times, and finally diffusive behavior again at long times. These three regimes observed in the experiments are compared with a theoretical model for the Langevin dynamics of self-propelled particles with coupled translational and rotational motion. Besides the mean square displacement also higher displacement moments are addressed. In particular, theoretical predictions regarding the non-Gaussian behavior of self-propelled particles are verified in the experiments. The non-Gaussianity is also clearly manifested in the displacement probability distribution of the Janus particles. In agreement with Brownian dynamics simulations, either an extremely broadened peak or a pronounced double-peak structure is found depending on the experimental conditions.