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Light driven Ag/AgCl-based Janus particles and their microenvironment

By: Larysa Baraban
From: TU Dresden, Germany
At: Online - Zoom (https://videoconf-colibri.zoom.us/j/84565677682?p
[2020-12-17] 10:00

Interactions between species are very common in nature ranging from microorganisms up to mammalians. Prominent examples include communication of individual cells and microorganisms with each other to form multicellular aggregates when lack of nutrients. Similar to biological systems, the study of interactions between synthetic actively moving objects and their environment represents a dynamic research field. The interest is primarily motivated by the fact that synthetic nano- and microswimmers moving due to the conversion of chemical energy into mechanical motion can mimic numerous functions of natural systems. The key goal is to achieve an efficient control of man-made microswimmers and understand their interaction with the microenvironment aiming to address broad range of applications ranging from MEMS and lab-on-a-chip systems through the accomplishment of complex tasks as nanomachinery, nanomedicine, all the way to (bio-) chemical sensing.We address these aspects by investigation of the interaction of visible light-driven spherical Janus particles embedded in a dense matrix of passive colloids, and well defined external potentials. In particular, we report on the anisotropy of the active-passive particles interaction in a system containing an immobile yet photochemical Ag/AgCl-based Janus particle embedded in a dense matrix of passive beads in pure water. Furthermore, we demonstrate – in experiments and in numerical simulations – a striking counter-intuitive behavior: the occurrence of long-range order in an initially disordered suspension of colloidal particles, driven by the presence of so-called ‘active defects’. Thus, we propose a novel route towards crystallization of matter under conditions far from equilibrium.