Regensburg 2010 – wissenschaftliches Programm
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SYMR: Symposium Nuclear Magnetic Resonance: from Applications in Condensed-Matter Physics to New Frontiers
SYMR 5: Nuclear Magnetic Resonance: Frontiers and Applications
SYMR 5.7: Vortrag
Dienstag, 23. März 2010, 15:15–15:30, H48
Structural characterization of lyotropic lamellar phases by NMR spectroscopy — Bruno Medronho1,2, Maria G. Miguel1, Ulf Olsson2, and •Claudia Schmidt3 — 1Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal — 2Physical Chemistry, Center of Chemistry and Chemical Engineering, Lund University, Box 124, 221 00 Lund, Sweden — 3Department of Chemistry, University of Paderborn, Warburger Str. 100, 33098 Paderborn, Germany
The lyotropic lamellar Lα phase is usually considered to consist of stacks of extended parallel layers. However, the application of shear may lead to defect structures consisting of close-packed multilamellar vesicles, also known as onions. Furthermore, it has been suggested that an intermediate structure of multilamellar cylinders occurs during the transformation from layers to vesicles. In this contribution we will give an overview on what kind of structural information can be obtained by deuterium NMR spectroscopy applied in situ under shear. It will be shown how different structures can be distinguished, how onions can be formed and destroyed by the application of shear and how the onion size can be measured on the basis of an NMR line shape analysis.