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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 21: POSTERS Colloids, Nanoparticles and Aggregates

CPP 21.27: Poster

Mittwoch, 27. Februar 2008, 16:00–18:30, Poster A

Hydrodynamics in colloidal suspensions: From highly charged to electrostatically screened particles — •Fabian Westermeier¹, Tina Autenrieth¹, Christian Gutt¹, Aymeric Robert², and Gerhard Grübel¹ — ¹Hasylab/DESY, Hamburg, Germany — ²SLAC/Stanford University, Menlo Park, USA

We studied the dynamic behaviour of charge-stabilised colloidal suspensions. For these systems the direct particle interactions, for which the experimental data can be described by the RMSA model, are well understood. For the indirect particle interactions which are mediated by the solvent and described by the hydrodynamic function several theories have been developed and experimentally tested within the last years, but there is no universally valid theoretical model that is applicable over the whole range of volume fractions.

Therefore we undertook a systematic study where the interaction strength between the particles was altered by varying both the volume fraction of the colloids and the concentration of added electrolyte screening the electrostatic interactions. The combined use of dynamic light scattering (DLS), Small Angle X-ray Scattering (SAXS) and X-ray Photon Correlation Spectroscopy (XPCS) allowed us the determination of the hydrodynamic function free from any modeling.