Dresden 2006 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 27: POSTER Polymer Physics and Materials
CPP 27.10: Poster
Donnerstag, 30. März 2006, 17:00–19:00, P2
Mixed monolayers of phospholipids and amphiphilic block copolymers at the air/water interface — •S. Raleva1, H. Hussain2, J. Kreßler2, V. Schön3, P. Huber3, and B. Stühn1 — 1TU Darmstadt, D-64289 Darmstadt — 2MLU Halle-Wittenberg, D-06099 Halle — 3University of Saarland, D-66041 Saarbrücken
We have investigated the behaviour of mixed monolayers of phospholipids and amphiphilic block copolymers at the air/water interface by measuring the surface pressure/area isotherms in conjunction with x-ray reflectivity measurements. The samples are the synthetic phospholipid diphytanoylphosphatidilcholine (DPhPC) and amphiphilic di- and triblock copolymers of poly(ethylene oxide) and poly(perfluorohexylethyl methacrylate). From the isotherms we obtain information about the monolayer conformation as a function of the degree of compression. From the x-ray reflectivity measurements we obtain information about the surface roughness, film thickness and electron density variation along the surface normal. We discuss the results as a function of the film composition and the surface pressure. DPhPC isotherms show that the phospholipid exists in the liquid-expanded phase at all surface pressures. The results of monolayer thickness at the air/water interface are in agreement with the results for monolayer of DPhPC on solid substrate. Analysis of the surface pressure/area isotherms shows that the addition of polymer results in homogeneously mixed as well as of non mixed films, depending on the concentration of the added polymer, its composition and surface pressure. X-ray reflectivity measurements results show clear change in the thickness of the film after addition of the polymer.