Berlin 2012 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 26: Poster: New Perspectives of Scattering at Soft Matter

CPP 26.7: Poster

Mittwoch, 28. März 2012, 11:00–13:00, Poster A

Easy use and low cost fibre based two color dynamic light scattering — Achim Lederer and •Hans Joachim Schöpe — Johannes Gutenberg-Universität Mainz, Institut für Physik, Staudinger Weg 7, 55099 Mainz, Deutschland

Light scattering (LS) is one of the most powerful tools in soft matter physics to study the single particle properties as well as the structure, kinetics and dynamics of the system of interest. Unfortunately multiple scattering often complicates the data evaluation. A classy way to circumvent multiple scattering effects in LS data is provided by cross-correlation techniques [1]. Here two identical but distinguishable dynamic light scattering experiments are performed simultaneously on the same scattering volume, which is a major challenge to the mechanical and optical design of the setup. We present a new designed small and compact two color cross correlation light scattering setup to study the structure and dynamics of colloidal suspensions in the regime of considerable turbidity. Using a home-made concentric four arm goniometer, combined with fiber optical illumination and detection devices allows an easy and long time stable alignment - even under temperature variation of ~5°C. Tests with a nearly multiple scattering free suspension of small Rayleigh scatterers show intercepts in cross correlation near 0.4 over a wide range of scattering angles from 20° to 150°. Measuring slightly turbid samples in cross correlation mode multiple scattering is sufficiently suppressed allowing the determination of multiple scattering free dynamic structure factors as well as particle form factors.[1] K. Schätzl, Journal of Modern Optics 38, 1849 (1991)