Regensburg 2010 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 46: Focus: Charge Effects in Soft and Biological Matter II (jointly with BP)
CPP 46.11: Vortrag
Donnerstag, 25. März 2010, 17:15–17:30, H37
Changes of the Molecular Structure in Supported Polyelectrolyte Multilayers under Mechanical Stress — •Johannes Früh1, Mareike Kiel1,2, Ralf Köhler1,3, and Rumen Krastev1,4 — 1Max Plank Institut für Kolloid- und Grenzflächenforschung, 14424 Potsdam, Germany — 2Uni Potsdam, 14476 Potsdam, Germany — 3Helmholtz-Zentrum Berlin, 14109 Berlin, Germany — 4NMI an der Universität Tübingen, 72770 Reutlingen, Germany
Polyelectrolyte multilayers (PEM) are extensively applied in contemporary technique. They are composed of oppositely charged polymers. The build-up process is based on the electrostatic interactions between the interface and the polymer molecules. Application of lateral stress on PEM changes the molecular conformation and the orientation of the polymers, and the electrostatic interactions between them. This leads to changes in the interfacial properties of the PEM coatings. The pyrene fluorescence is a tool to study the molecular coiling and polarity in PEM. We used this to follow the changes in the molecular structure of PEM prepared from pyrene labelled poly-styrene sulphonate and poly-(diallyldimethylammonium) chloride deposited on sheets of PDMS. We found that PEM undergo a plastic deformation under mechanical stretching. The polymer molecules organised in PEM experience a transition from coiled to decoiled state. The deformation strongly depends on the salt concentration of the solution from which the PEM are prepared, respectively on the molecular coiling and electrostatic interactions.