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PD Dr. Simone Wiegand

[Id: 4030]

[ 5819 Besucher ]

Institut für Physikalische Chemie
Luxemburger Str. 116
-50939 Köln

Raum:FZ Jülich
Tel:02461 616654
Fax:02461 612280

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The precise knowledge of transport coefficients as diffusion and viscosity in mixtures and solutions plays an important role in chemical processes. The experimental determination of these quantities is often more difficult than the determination of static properties since the system has to be moved into a non-equilibrium state. The sensitive holographic Thermal Diffusion Forced Rayleigh Scattering method is advantageous when studying the thermal diffusion process in binary mixtures close to the critical point and in ordinary mixtures, polymer solutions and colloidal dispersions. It only requires a relatively small displacement from equilibrium compared to other methods.

Conventional light-scattering is a powerful tool to study aggregation of macromolecules in solutions. Unfortunately, the experiments are limited to diluted samples due to the presence of multiple scattering in turbid samples. It has been shown that the 3D cross correlation technique is a useful tool to suppress multiple scattering in highly turbid solutions. A modified one-beam-cross correlation modification should be implemented into a conventional light-scattering set-up for routine measurements.


Experimental study of the thermal diffusion behaviour of mixtures consisting of simple and chain-like molecules


Simone Wiegand  studied physics at the University of Bielefeld where she received her diploma in 1988 working on diode pumped solid state laser at the Laser Center in Hannover. She received her PhD from the University of Bremen in 1993, studying phase transitions in binary mixtures close the critical point using light scattering methods. In 1994 she received a Feodor Lynen fellowship of the Humboldt foundation and worked at NIST in Gaithersburg (USA) on spinodal decomposition, viscosity and light scattering on ionic binary mixtures close to the critical point. Back in Germany in 1996, she initialized a project to study transport phenomena in complex fluids as salt mixtures, polymer solutions and gels in Bremen. In 1998 she moved to the Max Planck Institute for Polymer Research where she continued her research on the dynamic of complex fluids developing scattering techniques and headed the service group for polymer analysis (LINK zu ). In 2003 she received her habilitation from the University Bremen and joined the group of Jan Dhont at the Forschungszentrum in Jülich. In 2005 she completed her “Umhabilitation” at the university cologne.