Dresden 2003 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 22: Soft matter II
DY 22.6: Vortrag
Dienstag, 25. März 2003, 12:00–12:15, G\"OR/226
Wetting morphologies on topographically structured substrates — •Ralf Seemann1,2, Edward Kramer1, Fred Lange1, Martin Brinkmann3, and Reinhard Lipowsky3 — 1University of California, Santa Barbara — 2Dept. of Applied Physics, University of Ulm — 3MPI of Colloids and Interfaces, Golm
We have studied, both experimentally and theoretically, the wetting behavior of a liquid in rectangular grooves with chemically homogeneous walls. The length scale has been chosen to be small compared to the capillary length in order to avoid gravitational effects, but large enough for long range wetting forces (such as the van der Waals force) to be irrelevant. We derived theoretically the morphological phase diagram of liquid channels confined in the grooves as function of aspect ratio and contact angle. The results are in excellent agreement with our experimental findings. Droplets form elongated morphologies for large aspect ratios and high wettability of the substrate. For sufficiently small aspect ratios no confinement occurs. Also for contact angles smaller than a critical value it is not possible to confine some liquid in the grooves; here we found interesting new wetting morphologies.