Regensburg 2022 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 5: Wetting, Droplets and Microfluidics (joint session DY/CPP)
CPP 5.8: Vortrag
Montag, 5. September 2022, 12:00–12:15, H19
Active thin films — •Tilman Richter1, Paolo Malgaretti1, Stefan Zitz2, and Jens Harting1 — 1Forschungszentrum Jülich GmbH, Helmholtz Institute Erlangen- Nürnberg (IEK-11), Dynamics of Complex Fluids and Interfaces, Cauerstraße 1, 91058 Erlangen, Germany — 2Roskilde University, Department of Science and Environment, Roskilde, Denmark
Thin liquid films are important for many microfluidic applications such as printing or coating of e.g. printable electronics or photovoltaic cells where a evenly spread thin film of certain properties is of utmost importance. It is well known that a thin film on a solid substrate can be unstable and droplet formation may arise, especially for very thin films. The dynamics of thin liquid films and their instability has been the subject of intensive experimental, analytical, and numerical studies, the latter often based on the thin film equation. We propose a set of newly developed equations for the influence of chemical active colloids suspended in a thin liquid film based on the lubrication approximation, advection-diffusion and, the Fick-Jackobs approximation. For this novel set of equations we perform a linear stability analysis (LSA) that reveals surprisingly interesting dynamics. We identify the subset of parameters for which the thin film becomes stable, as well as a variety of different dominating wave-modes. This allows us to control not only the stability but also the droplet size distribution after film rupture. In order to assess the asymptotic state of the thin film, the LSA results are compared against numerical simulations using the Lattice Boltzmann method.