Dresden 2009 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 38: POSTERS Micro- and Nanofluidics
CPP 38.7: Poster
Donnerstag, 26. März 2009, 17:00–19:30, P3
Near-Surface Structure and Dynamics Explored by Grazing Incidence Neutron Scattering — •Marco Walz1, Max Wolff2,3, Nicole Voss1, Philipp Gutfreund2,3, Hartmut Zabel1, and Andreas Magerl1 — 1Crystallography and Structural Physics, Univ. Erlangen-Nürnberg — 2Solid State Physics, Ruhr-Univ. Bochum, Germany — 3Institut Laue-Langevin, Grenoble, France
Even in simple fluids the conventional non-slip boundary condition becomes microscopically void. Surface slip characterized by the slip length may become macroscopic, and a large slip length implies a pronounced anomaly in the shear flow adjacent to a solid surface, where the anomaly itself is only present in a thin layer next to the solid interface within the order of nanometers. For an understanding of boundary slip, the anomalies in the structural and dynamical properties in the interface layer need to be understood. To highlight the properties of the boundary layer we carried out Grazing Incidence Small Angle Neutron Scattering (GISANS) and, for the first time, a Neutron Spin-Echo experiment under condition of Grazing Incidence (GINSE). Our investigation of a concentrated tri-block copolymer solution shows that the local structure depends on the distance to the interface and the chemical termination of the solid boundary. However, the key for the understanding of slip may also be related to a change in the local dynamics of a liquid at an interface and under flow. We have verified that the investigation of the dynamics of the sample with the GINSE technique is feasible, and we present data taken near the critical angle of total reflection.