Seminar über aktuelle Fragen zur Dynamik komplexer Fluide: Symmetry breaking in chemically active microdrops grants an insight into interfacial chemistry

Seminar über aktuelle Fragen zur Dynamik komplexer Fluide

  • Datum: 15.01.2021
  • Uhrzeit: 10:15 - 11:15
  • Vortragende(r): Matvey Morozov
  • Université libre de Bruxelles, Belgium
  • Ort: Max-Planck-Institut für Dynamik und Selbstorganisation (MPIDS)
  • Raum: Video conference at, Meeting ID: 980 3913 9623, Passcode: 050762
  • Gastgeber: MPIDS/DCF
  • Kontakt:
A chemically-active microdrop that is suspended in the bulk of a reagent solution is an example of a non-equilibrium physicochemical system akin to cells and vesicles. Owing to their non-equilibrium nature, active drops may excite the flow in the surrounding fluid even in the absence of preexisting asymmetries, such as gravity or inhomogeneous interfacial properties. In experiments, this spontaneous flow excitation results in active drops self-deforming or self-propelling along a straight, helical, or chaotic trajectory.
In this talk, we will discuss two theoretical models that explain self-propulsion regime selection based on droplets' interfacial properties. The first model corresponds to the case of a slow chemical reaction and demonstrates that in active drops of a nematic liquid crystal, coupling of the flow field and liquid crystal configuration may result in a novel mode of orientational instability leading to helical self-propulsion trajectory. The second model focuses on the case of intense chemical reaction. Our key finding is that in the case of axisymmetric flow and concentration fields, two qualitatively different types of droplet behavior may be stable for the same values of the physical parameters: steady self-propulsion and steady symmetric pumping. This multistability suggests that there is a new class of active matter models to be investigated.
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