Electrifying active matter - Petia M. Vlahovska (Northwestern University, U.S.A.)

Bird flocks and fish schools move around like fluid when viewed on a scale much larger than the individuals. Similar large-scale coherent motions have been observed with self-propelled micro-particles such as bacteria and motile colloids. In this talk, I will discuss the collective dynamics of particles activated by electric fields, e.g., the Quincke instability (spontaneous spinning of a dielectric particle in an applied uniform DC field) which makes the particles roll on a surface.  I will present our experiments showing how Quincke rollers can be designed to perform Run-and-Tumble-like locomotion mimicking bacteria such as E. coli. Populations of these Quincke random walkers self-organize and exhibit behaviors reminiscent of bacterial suspensions such as dynamic clustering and mesoscale turbulent-like flows, and new behaviors such as emergent multi-vortex states. When enclosed in a drop, the Quincke rollers drive strong shape fluctuations and drop motility resembling amoeba crawling. Finally, I will show how electrohydrodynamic flows can drive droplets to tandem-swim.

Contact: Alexander Farutin