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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 79: Microswimmers, Active Liquids II (joint session CPP, BP, DY)

CPP 79.3: Vortrag

Freitag, 20. März 2015, 10:15–10:30, C 264

Dynamics of a carpet of self-propelled surfactant particles covering a liquid film — Andrey Pototsky¹, •Uwe Thiele², and Holger Stark³ — ¹Department of Mathematics, Swinburne University of Technology, Hawthorn, Victoria, 3122, Australia — ²Institut für Theoretische Physik, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany — ³Institut für Theoretische Physik, Technische Universität Berlin, 10623, Berlin, Germany

We consider a carpet of self-propelled surface-active particles that move along the liquid-gas interface of a liquid film on a solid substrate and whose swimming direction changes in time due to rotational diffusion. We study the intricate influence of these self-propelled insoluble surfactants on the stability of the film surface and show that depending on the strength of in-surface rotational diffusion and the absolute value of the in-surface velocity several instability modes can occur [1]. In particular, the rotational diffusion can have a stabilizing or destabilizing influence and may even suppress the instability entirely. In the limit of purely upwards swimming we recover the destabilisation described in the literature [2]. The results of the linear analysis are confirmed by fully nonlinear simulations of the complete continuum model and as well through a hybrid discrete self-propelled surfactant particles - continuous film model. [1] A. Pototsky, U. Thiele and H. Stark, Phys. Rev. E 90, 030401(R) (2014). [2] S. Alonso and A.S. Mikhailov, Phys. Rev. E 79, 061906 (2009).