Berlin 2012 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 16: Poster: Colloids and Complex Liquids

CPP 16.20: Poster

Tuesday, March 27, 2012, 18:15–20:45, Poster A

Confocal Microscopy of Colloidal Hard Sphere and Charged Sphere Fluids and Crystals — •Achim Lederer and Hans Joachim Schöpe — Johannes Gutenberg University, Mainz, Germany

Monodisperse suspensions of colloidal spheres with known interaction are a terrific model system for testing predictions by statistical physics. Their typical length scales are accessible via optical methods like light scattering in reciprocal and microscopy in real space. Light scattering leads to ensemble averaged observables like structure factors in reciprocal space with a high statistical accuracy, while information about the local order and the local dynamic are very difficult to get. A state-of-the-art technique to gain information about the local parameters of a colloidal system is the Laser Scanning Confocal Microscope (LSCM) which takes 3D-videos from a sample. By this method, the structure and dynamics of a colloidal suspension can be observed on a single particle scale ([1], [2]). In this work we investigate colloidal model systems with hard sphere and charged sphere interaction in the fluid and crystalline regime using LSCM. We determine the structure of the colloidal fluid in the equilibrium state as well as in the metastable regime showing significant differences between these states increasing with increasing metastability.

[1] V. Prasad et al., J. Phys.: Condens. Matter 19, 113102 (2007).

[2] A. D. Dinsmore et al., Appl. Opt. 40, 4152 (2001)