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BP: Fachverband Biologische Physik
BP 28: Focus: Charge Effects in Soft and Biological Matter II (joint CPP, BP, ST)
BP 28.12: Vortrag
Donnerstag, 25. März 2010, 17:30–17:45, H37
About the interfacial behaviour of PEM films of different charge density — •Ralf Köhler1,2, Ingo Dönch1, Patrick Ott3, André Laschewsky3, Andreas Fery4, and Rumen Krastev1,5 — 1MPI of Colloids and Interfaces, 14424 Potsdam — 2Helmholtz Centre Berlin for Materials and Energy, 14109 Berlin — 3University of Potsdam, 14476 Potsdam — 4University of Bayreuth, 95440 Bayreuth — 5NMI at the University of Tübingen, 72770 Reutlingen, Germany
Polyelectrolyte Multilayers (PEM) consist in complexed layers of organic polyions of opposite charge build-up on solid substrate by layer-by-layer deposition. Although PEM materials are studied since more than a decade, the interplay of internal interactions and structure is still far from being understood.
We investigate the internal structure of PEM by means of swelling experiments, i.e. an internal mechanical stress is induced into PEM by uptake of solvent molecules from adjacent solvent vapour (H2O) of varying saturation. 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.
Three different PEM systems made from PSS/PDDA (1) are investigated; each containing a derivative of the polycation PDDA of 75, 89, or 100% charge density, also the number of adsorbed layers is varied.
It shows that the swelling characteristics changes continuously with the initial film thickness indicating internal transitions of structure and swelling. (1) poly-styrene sulphonate/ poly-diallyldimethyl ammonium