Dresden 2009 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 18: Polyelectrolytes

CPP 18.8: Talk

Tuesday, March 24, 2009, 11:30–11:45, ZEU 114

Bundle Formation in Polyelectrolyte Brushes — Jens-Uwe Günther, •Heiko Ahrens, and Christiane A. Helm — Institut für Physik, Uni Greifswald, Felix-Hausdorff-Str. 6, 17487 Greifswald

Bundle formation in the vertically oriented polyelectrolytes within polyelectrolyte brushes is studied with x-ray reflectivity and grazing-incidence diffraction as a function of grafting density and ion concentration. At 0.5 Molar monomer concentration and without added salt, a bundle consists of two chains and is 5 nm long. On the addition of up to 1M CsCl, the aggregation number increases up to 15 whereas the bundle length approaches a limiting value, 2 nm. We suggest that the bundle formation is determined by a balance between long-ranged electrostatic repulsion, whose range and amplitude is decreased on salt addition, and short-ranged attraction.