Regensburg 2010 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

CPP: Fachverband Chemische Physik und Polymerphysik

CPP 46: Focus: Charge Effects in Soft and Biological Matter II (jointly with BP)

CPP 46.11: Talk

Thursday, March 25, 2010, 17:15–17:30, H37

Changes of the Molecular Structure in Supported Polyelectrolyte Multilayers under Mechanical Stress — •Johannes Früh¹, Mareike Kiel^1,2, Ralf Köhler^1,3, and Rumen Krastev^1,4 — 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.