Regensburg 2007 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 19: POSTER: Micro and Nano Fluidics
CPP 19.19: Poster
Mittwoch, 28. März 2007, 16:00–18:30, Poster B
Towards a microscopic understanding of slip — •Dorothee Meier1, Max Wolff1, Marco Walz2, Nicole Voss2, Renate Fetzer3, Karin Jacobs3, Andreas Magerl2, and Hartmut Zabel1 — 1Lehrstuhl für Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany — 2Lehrstuhl für Kristallographie und Strukturphysik, Universität Erlangen-Nürnberg, 91058 Erlangen, Germany — 3Lehrstuhl für Weiche Kondensierte Materie, Universität des Saarlandes, 66041 Saarbrücken, Germany
In recent years, the increasing interest in flow in confined geometries has raised the need for a deeper understanding of the microscopic origin of boundary slip.
Neutrons are exceptionally well suited for the investigation of soft matter systems. This is related to their high transmittance through many kinds of materials as well as to the high scattering length density of deuterium in comparison to the x-ray cross section of hydrogen. Furthermore, sample properties can be tuned via isotopic substitution.
We have investigated the density in the near surface region in systems which undergo boundary slip via neutron and x-ray reflectometry. Our model systems are stationary and flowing liquids in contact with polystyrene coated silicon crystals as well as polystyrene films on OTS and DTS grafted to a silicon wafer. The reflectivities show differences in the density profiles of systems which are known to undergo slip in comparison to non-slipping samples. This could be related to different interdiffusion properties of the distinct substances used.
This work is supported by the DFG Priority Program SPP 1164.