Regensburg 2010 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 30: Poster: Micro and Nanofluidics
CPP 30.8: Poster
Wednesday, March 24, 2010, 17:30–19:00, Poster C
Static Wetting Morphologies in Topographically Structured Substrates — •Stefan Bommer1, Dominik Michler1, Martin Brinkmann2, and Ralf Seemann1 — 1Saarland University, Experimental Physics,D-66041 Saarbrücken — 2MPI for Dynamics and Self-Organisation,Bunsenstrasse 10, D-37073 Göttingen
The different wetting morphologies of liquid confined to micron sized trapezoidal grooves are studied experimentally and theoretically. We explore the emerging equilibrium morphologies as function of groove wettability and groove aspect ratio, i.e. the ratio of the groove depth to the groove width. For big aspect ratio the qualitative wetting behavior is expected to be similar to triangular grooves, whereas for decreasing aspect ratio the wetting behavior of rectangular grooves or even individual topographic steps is expected. The grooves are fabricated in silicon by wet etching, whereas the slope of the side walls is given by the crystal lattice of the silicon. The wettability of the substrate is controlled by various self-assembly monolayers and fine tuned with a subsequent oxygen plasma treatment. The wetting morphologies consist of polystyrene deposited from the gas phase and imaged by scanning force microscopy in an intermitted. A morphological diagram is derived analytically by minimizing the surface free energies and using the available software package "Surface Evolver" and compared to the experimental results.