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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 48: Colloids and Complex Liquids III

CPP 48.1: Topical Talk

Friday, March 26, 2010, 10:15–10:45, H39

Structural arrangement and picosecond dynamics of phospholipids in colloidal systems — •Tobias Unruh, Sebastian Busch, and Martin Schmiele — Technische Universität München, Forschungsneutronenquelle Heinz Maier-Leibnitz and Physik Department E13, 85747 Garching

Phospholipids (PL) are extensively studied for decades mainly because they form the dominant constituent of biological membrans. Furthermore, PL are widely used for stabilization of dispersions, solubilization of hardly soluble substances, and as liposomes and vesicles in food and pharmaceutical industry. However, only little is known so far about the molecular arrangement and dynamics of the stabilizing PL layers in native, technological relevant nanodispersions.

In this talk it will be demonstrated that it is possible to gain detailed structural information about the PL stabilizer layer in nanodispersions by combining X-ray and neutron small angle scattering studies with ab initio calculations of the complex scattering patterns. The mobility of PL molecules in the liquid crystalline phase but also in the stabilizer layer of nanodispersions was studied by quasi elastic neutron scattering. Using this method it could be observed that on a picosecond time scale PL molecules perform rather a directed flow-like (collective) motion than a random walk-like diffusive motion. This observation is essential for the understanding of transport processes in biological membranes over distances in the lower nanometer range and is found to be in excellent agreement to recent molecular dynamics simulations.