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BP: Fachverband Biologische Physik

BP 7: Active Fluids and Microswimmers (joint session DY/BP/CPP)

BP 7.8: Vortrag

Montag, 18. März 2024, 17:15–17:30, BH-N 243

Artificial Microswimmers in locally-tuneable hydrodynamic flow fields — •Lisa Rohde and Frank Cichos — Molecular Nanophotonics Group, Peter-Debye-Institute for Soft Matter Physics, University Leipzig, Leipzig, Germany

Biological components on the microscale, which constantly consume energy can organize themselves into functional structures through interaction with their environment. Interaction potentials, temperature or composition gradients as well as flow fields play an important role in this structure formation. We would like to transfer such self-organization principles to synthetic active particles, which are a model system to mimic the function of motors in biology, but yet have only limited functionality. Here, we expose thermo-phoretic Janus particles to an environment with tuneable hydrodynamic flow fields generated by local temperature gradients. A heated paramagnetic silica particle acts as a heat source and generates a thermo-osmotic flow field due to a temperature gradient on the substrate. By controlling the temperature of the heat source, we are able to locally change the generated hydrodynamic flow field. We study the orientational dynamics and the distance of the Janus particles relative to the heat source in dependence of temperature and laser intensities. The interplay of the local flow fields with the activity of the Janus particles results in a potential that traps the Janus particles in a configuration around the heat source. We find a polarisation of the Janus particles that align with the flow field having a stable orientation relative to the heat source.

Keywords: microswimmers; hydrodynamics; self-organization; active particles