Berlin 2012 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 19: Charged Soft Matter

CPP 19.4: Talk

Wednesday, March 28, 2012, 10:15–10:30, C 243

Electro-kinetics of Charged Sphere Suspensions Explored by Integral Low Angle Super-Heterodyne Laser Doppler Velocimetry — •Bastian Sieber, Holger Schweinfurth, Tetyana Köller, and Thomas Palberg — Johannes Gutenberg Universität, D-55128 Mainz, Germany

We investigated the flow behaviour of colloidal charged-sphere suspensions using a newly designed integral low angle super-heterodyne laser Doppler velocimetry which combines the advantages of several previous approaches. The obtained power spectra correspond to diffusion broadened velocity distributions across the complete sample cross section. The excellent performance of the instrument is highlighted in detail at the example of electro-kinetic flow of suspensions in a closed cell of rectangular cross section. We demonstrate that our instrument allows for convenient and simultaneous quantitative determination of the electro-phoretic mobility, the electro-osmotic mobility, the particle flow profile, an effective diffusion coefficient, and the spectral power as a function of interaction conditions.