Regensburg 2019 – wissenschaftliches Programm
DY 44.1: Vortrag
Donnerstag, 4. April 2019, 10:00–10:15, H19
Self-propelled Janus particles in evaporating droplets — Maziyar Jalaal1,2, Borge Ten Hagen1, Hai Le The3, Christian Diddens1, Detlef Lohse1,2, and •Alvaro Marin1 — 1Physics of Fluids, University of Twente, The Netherlands — 2Max-Planck Center for Complex Fluid Dynamics, University of Twente, The Netherlands — 3BIOS-Lab on a Chip, University of Twente, The Netherlands
According the kids britannica encyclopedia: “Living things have the ability to move in some way without outside help.”. Following this precise definition, artificial self-propelled particles are not alive, but they almost are since they move taking advantage of chemical/physical reactions or more complex interactions with their environment. Such active particles have been developed and thoroughly characterized in recent years in vitro: in either quiescent liquid media or stationary flow fields. However, in most situations living things encounter unsteady flows and interfaces of different types. To approach more realistic situations, we choose to study the dynamics of self-propelling Janus particles in evaporating droplets. Our system consists on polysterene-platinum Janus colloids immersed in a sessile droplet containing an hydrogen peroxide solution. The system is analyzed using three-dimensional particle tracking measurements and numerical simulations of the nontrivial fluid flow within the evaporating droplet. To our surprise, the dynamics of the active particles turns to be extremely rich due to several mechanisms as the proximity to interfaces, concentration gradients and evaporation-driven flows.