Max Planck Intelligent Systems Colloquium, Stuttgart

9398 1489659657

Tactic Response of Synthetic Microswimmers in Gravitational and Optical Fields

  • Date: Apr 5, 2017
  • Time: 11:00
  • Speaker: Prof. Dr. Clemens Bechinger, Head of the 2nd Institute of Physics, University of Stuttgart
  • Location: MPI IS Stuttgart, Heisenbergstr. 3
  • Room: 3P 2
  • Host: Prof. Dr. Metin Sitti, Managing Director, Max Planck Institute for Intelligent Systems
  • Contact:


Many motile organisms have developed intriguing steering mechanisms allowing them to orientate and navigate within gravitational, chemical or light fields. Such tactic response is an essential aspect of life since it facilitates e.g., the search for food, reproduction and/or escape from unfavorable ambient conditions. Unlike living systems, where tactic behavior is typically achieved by complex internal signal pathways, it is not obvious how it can be imposed on synthetic microswimmers, which are typically much simpler regarding their internal structure. Using light-activated self-propelled particles, Prof. Bechinger and his colleagues demonstrate autonomous steering in gravitational fields and light gradients, which is achieved by the combination of viscous forces and torques which naturally arise in our system. Their findings are confirmed by theory and simulations and suggest that similar tactic response should also occur for other propulsion mechanisms. Clemens Bechinger’s group is largely interested in colloidal systems, i.e. mesoscopic particles with diameters of 10 – 1000 nanometers which are suspended in a liquid. Although colloids are much larger than atoms, both systems are essentially driven by the same underlying equations and therefore share many properties. This similarity is particularly striking in situations which are governed by structural aspects or fluctuations as being important for phase transitions, glass formation, critical and dissipation phenomena etc. In contrast to atomic systems where the interactions are dictated by the electronic structure, in colloidal systems they can be largely tuned by external parameters such as optical, electrical or magnetic fields. This distinguishes colloids as versatile model systems which become increasingly important for the understanding of fundamental processes in solid state and material science but also for experimental tests of theories related to statistical physics.


Prof. Dr. Clemens Bechinger holds a position of the Head of the 2nd Institute of Physics at the University of Stuttgart. He graduated in Physics from the University of Heidelberg (Germany) in 1990. He then moved on to the Physics Department of the University of Konstanz (Germany), where he obtained his PhD in 1993. Prof. Bechinger continued working at the University of Konstanz as a Research Associate until 1994. In 1995 he joined National Renewable Energy Laboratory in Denver (USA) as a Research Associate and a DFG fellow. Prof. Bechinger completed his habilitation at the University of Konstanz, Department of Experimental Physics, in 1999 and worked there as a lecturer until 2003. Since 2003 Prof. Bechinger is the Head of the 2nd Institute of Physics at the University of Stuttgart.

The research interests of Prof. Bechinger focus on active Brownian motion, microrheology in viscoelastic liquids, critical phenomena in colloidal suspensions, microscopic thermodynamics, colloidal quasicrystals, friction at microscopic length scales, separation of chiral objects in microfluidic devices as well as transport and flow through porous media. Prof. Bechinger has received several prizes and awards including Dornier Research Award for the PhD thesis on photochromic thin films in 1995, LBS Environment prize for the concept and realization of a self-contained, smart window in 1997, Walter Schottky prize for the investigation on structural properties and phase transitions with colloidal model systems in 2000, Max Planck Research Fellow at the MPI for Metal Research/MPI for Intelligent Systems in 2007 and 2012 as well as ERC Advanced Grant in 2016.

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