Berlin 2018 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 31: Microswimmers DY II (joint session DY/CPP/BP)

BP 31.12: Vortrag

Donnerstag, 15. März 2018, 13:00–13:15, BH-N 243

The droplet divisome — Kyle A. Baldwin, Babak Vajdi Hokmabad, and •Corinna C. Maass — MPI für Dynamik und Selbstorganisation Göttingen

Active emulsions of nematic liquid crystals in micellar surfactant solutions are a flexible and well controlled model system for microswimmers, exhibiting a wealth of features like helical swimming, convection driven clustering, chemotaxis and autochemotaxis. Their propulsion is driven by Marangoni stresses caused by self-supporting instabilities in the interfacial surfactant coverage. Generally, such surface tension variations should deform the droplet interface, but we have not seen measurable deviations from a spherical shape for  50µm droplets in Hele-Shaw cells due to strong capillary forces. However, in experiments using squeezed droplets, i.e. larger, more disk-shaped objects in strong two-dimensional confinement, capillary forces are weakened due to an effective switch from areal to line tension and a decrease of the deformable interface to volume ratio. We have observed multipolar Marangoni instabilities, visible deformation during self propulsion and a spontaneous self division cascade for arrested droplets.