Berlin 2008 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 34: POSTERS Polymerphysics

CPP 34.57: Poster

Thursday, February 28, 2008, 17:00–19:30, Poster A

Influence of preparation conditions on lateral and vertical surface structure of polyelectrolyte multilayers — •Matthias Cornelsen, Stephan Block, Manesh Gopinadhan, and Christiane A. Helm — Institut für Physik, Ernst-Moritz-Arndt Universität, Felix-Hausdorff-Str. 6, D-17487 Greifswald, Germany

Polyelectrolyte multilayers from PAH and PSS are formed at different ion concentrations and temperatures. If the electrostatic force is screened (i.e. the ion concentration exceeds 0.05 M), then the film thickness increases on the rise of both temperature and salt concentration. However, for each salt concentration there is a maximum temperature up to which stable films can be formed. If films from temperatures 40 to 5 K below this maximum temperature are compared, one finds with X-ray reflectivity that the film/air roughness increases (from 1 to 4.5 nm) on approach to the maximum temperature. Also, with AFM a surface coarsening is observed on the scale of 150 to 300 nm. Furthermore, the average distance between height maxima is measured, which changes depending on preparation conditions from 15 to 30 nm. These maxima may be attributed to coils or parts of coils of single chains.