Berlin 2015 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 46: P11: Wetting, Micro and Nano Fluidics
CPP 46.4: Poster
Mittwoch, 18. März 2015, 10:00–13:00, Poster A
Liquid-liquid dewetting — •Stefan Bommer1, Nikolas Becker1, Ralf Seemann1, Sebastian Jachalski2, Dirk Peschka2 und Barbara Wagner2 — 1Universität des Saarlandes — 2TU Berlin
The transient morphologies towards equilibrium of liquid droplets dewetting on another liquid as well as the dynamics of dewetting rims are considered experimentally and theoretically. As liquids short chained polystyrene and polymethylmethacrylate are used which are glassy at room temperature and which can be considered as Newtonian liquids well above their glass transition temperatures. The liquid/air interfaces are imaged in situ by scanning force microscopy whereas the liquid/liquid interface is imaged after solidifying the sample and removing the dewetting polystyrene. The transient shapes are modeled by lubrication approximation and Stokes model using the relevant experimental parameters like the ratio of film thicknesses, the viscosity rations, the ratio of the surface tensions of the liquid/air and the liquid/liquid interface, and the contact angles. A remarkably independence of the transient shapes on the start conditions was found theoretically for sufficiently 'mature' droplets which allow for a quantitative comparison with experimental droplet morphologies. Carrying on from this successful comparison, we also investigate the shape and dynamics of dewetting rim profiles.