Dresden 2009 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 18: Polyelectrolytes
CPP 18.10: Vortrag
Dienstag, 24. März 2009, 12:00–12:15, ZEU 114
Change in Molecular Ordering in Mechanically Stressed Polyelectrolyte Films — Johannes Früh1, Rumen Krastev2, and •Ralf Köhler3,1 — 1MPI of Colloids and Interfaces, Dept. Interfaces, Potsdam, Germany — 2NMI, WB Bioanalytik, Tübingen, Germany — 3Helmholtz Centre Berlin for Materials and Energy, Dept. SF1, Berlin, Germany
Polyelectrolyte Multilayers (PEM) are organic films which consist in complexed layers of two polyions of opposite charge commonly build-up on solid substrate. The widely used layer-by-layer preparation method allows for a high tunability of the properties of the PEM. Although several studies exist about mechanical behaviour of these films, relatively little is known about the underlying internal structure and the structural changes on molecular level caused by external load/stimulus.
We are interested in the local distribution of micro- and mesoscopic substructures in the PEM-network (e.g., voids or cross-linker points) and their implications on general macroscopic properties, as stability and reversibility (ageing, fatigue) of the films. Especially the effects of external and internal mechanical load shall be examined.
Two strategies are pursued: firstly, the manipulation of internal mechanical stress by incorporation of solvent molecules into the polymer network (swelling experiments); and secondly, the application of external mechanical stress on soft matter-supported PEM samples. Here neutron reflectometry proofs to be a powerful tool due to its ability to test for the thickness of the sample and for its specific material content at the same time.