Berlin 2008 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 22: POSTERS Micro- and Nanofluidics
CPP 22.13: Poster
Mittwoch, 27. Februar 2008, 16:00–18:30, Poster A
Quasistationary dynamics of droplets on chemically structured substrates — Fabian Dörfler1,2, •Markus Rauscher1,2, and Siegfried Dietrich1,2 — 1Max-Planck-Institut für Metallforschung, Stuttgart, Germany — 2ITAP, Universität Stuttgart, Stuttgart, Germany
With open microfluidic systems in mind, we study the dynamics of droplets on chemical channels (i.e., hydrophilic stripes on otherwise hydrophobic substrates) in the quasistatic limit using the software Surface Evolver. In particular, we investigate the free energy landscape of droplets on symmetric Y-junctions in the capillary model. We find an energetic minimum right at the junction. There is a maximum in the energy landscape between two branches but no local minimum which might indicate the splitting of droplets. In addition, we find, that moving a droplet into a junction and back into a channel can result in a metastable elongated droplet shape.
We also investigate methods to include the substrate potential (i.e., the effect of long-ranged intermolecular interactions) into the Surface Evolver in order to apply this software to nanoscale droplets.