Dresden 2017 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 37: Aktive Matter I (joint session DY/BP/CPP)

DY 37.11: Vortrag

Mittwoch, 22. März 2017, 17:45–18:00, HÜL 186

Dynamics of model bacteria in dense polymer suspensions and networks — •Andreas Zöttl and Julia M Yeomans — Rudolf Peierls Centre for Theoretical Physics, University of Oxford, UK

Swimming bacteria, such as Helicobacter pylori, Pseudomonas aeruginosa and sperm cells, move through viscoelastic fluids, such as mucus, in vivo. Theoretical models for these complex fluids are typically based on continuum equations which assume a constant density of sufficiently small polymers, homogeneously embedded in a Newtonian fluid. However, real viscoelastic fluids are more structured when considered on the length scale of a microswimmer: they can consist of heterogeneously distributed, up to micrometer long, macromolecules such as mucin polymers.

Here we present results of coarse-grained hydrodynamic simulations of a flagellated bacterium swimming in explicitly modeled macromolecular polymer solutions and cross-linked networks. We find a remarkable increase in the bacterium’s swimming speed at high polymer density. We further discuss the effect of polymer properties such as length, stiffness and cross-linking. We also report the flow fields and the local polymer properties in the vicinity of the bacterium, which can be strongly influenced by its motion.