2020/04/08 by Matvey Morozov, Morozov, Matvey
Biochemistry, Genetics and Molecular Biology · Materials Science · Physics and Astronomy · #Biological Physics (physics.bio-ph) #Diffusion and Search Dynamics #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Micro and Nano Robotics #Pickering emulsions and particle stabilization #Soft Condensed Matter (cond-mat.soft)
paper · pdf · doi:10.48550/arxiv.2004.04149
openalex publication_date 2020/04/08 · openalex created_date 2022/07/26 · openalex updated_date 2026/07/28
Experiments indicate that microdroplets undergoing micellar solubilization in\nthe bulk of surfactant solution may excite Marangoni flows and self-propel\nspontaneously. Surprisingly, self-propulsion emerges even when the critical\nmicelle concentration is exceeded and the Marangoni effect should be saturated.\nTo explain this, we propose a novel model of a dissolving active droplet that\nis based on two fundamental assumptions: (a) products of the solubilization may\ninhibit surfactant adsorption; (b) solubilization prevents the formation of a\nmonolayer of surfactant molecules at the droplet interface. We use numerical\nsimulations and asymptotic methods to demonstrate that our model indeed\nfeatures spontaneous droplet self-propulsion. Our key finding is that in the\ncase of axisymmetric flow and concentration fields, two qualitatively different\ntypes of droplet behavior may be stable for the same values of the physical\nparameters: steady self-propulsion and steady symmetric pumping. Although\nstability of these steady regimes is not guaranteed in the absence of axial\nsymmetry, we argue that they will retain their respective stable manifolds in\nthe phase space of a fully 3D problem.\n