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DY: Dynamik und Statistische Physik

DY 45: Soft Matter

DY 45.6: Vortrag

Donnerstag, 30. März 2006, 15:45–16:00, SCH 251

Surface dynamics of capillary waves close to the glass transiton - Experiments with static and dynamic x-ray scattering — •Christian Gutt^1,2, Henning Sternemann², Michael Paulus², Simone Streit², Anders Madsen³, Michael Sprung⁴, and Metin Tolan² — ¹Hasylab at DESY, Notkestrasse 85, 22607 Hamburg — ²Experimentelle Physik I, Universität Dortmund — ³ESRF, Grenoble, France — ⁴Advanced Photon Source, ANL, Argonne, IL

Liquid surfaces are subject to thermally excited capillary waves which produce a surface roughness of a few Angstrom. Our surface scattering experiments with synchrotron radiation address the question of how these hydrodynamic surface modes become arrested close to the bulk glass transition. For this purpose x-ray reflectivity, grazing incidence diffraction and x-ray photon correlation spectroscopy experiments have been performed. The experiments cover a broad temperature range from room temperature down to temperatures close to the bulk glass transition at 180K. We were able to measure the temperature dependent surface roughness [1], the static height-height correlation function on a lengthscale of nanometers and the dynamic structure factor of the capillary wave fluctuations. The results are compared with theoretical predictions on the freezing behavior of capillary waves at the glass transition [2].

[1] M. Sprung et al. Phys.Rev. E 70, 051809 (2004) [2] J. Jäckle and K. Kawasaki, J.Phys.:Condens.Matter 7, 4351 (1998)