Dresden 2011 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 44: Micro- and Nanofluidics I
CPP 44.8: Vortrag
Donnerstag, 17. März 2011, 15:45–16:00, ZEU 160
Anisotropic wetting behavior on groove patterns — •Ciro Semprebon1, Carsten Herrmann2, Ralf Seemann2, Stephan Herminghauss1, and Martin Brinkmann1 — 1MPI for Dynamics and Self-Organization, Goettingen — 2Universitat des Saarlandes, Saarbrucken
We investigate theoretically and experimentally the shape of small liquid droplets condensing on a substrate decorated with periodic micro-patterns of parallel grooves. Depending on the pattern geometry and substrate wettability these droplets may either grow solely in the direction of the grooves forming elongated filaments, or spread anisotropically in both directions. In the spreading regime the droplet eccentricity oscillates as the number of wet grooves increases, ultimately reaching a scale invariant shape with a well defined anisotropy. The boundaries of the stability of filaments can be computed from an analytical model and depend on the number of grooves which are wet. Generally we find that the region of stability of filaments is smaller for filaments wetting a larger number of grooves. For the particular case of V-grooves the filaments may undergo either a Rayleigh-Plateau instability or lateral depinning of the contact line. The scale invariant shape can be described with a numerical model for liquid droplets confined to a single wettable stripe.