Berlin 2005 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 30: POSTER: Chemical physics

CPP 30.40: Poster

Dienstag, 8. März 2005, 16:30–18:30, Poster TU D

Investigation of the Internal Structure of Polyelectrolyte Multilayers by means of Neutral Impact Collision Ion Scattering Spectroscopy — •Thomas Krebs, Gunther Andersson, and Harald Morgner — Universität Leipzig, Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Linnéstrasse 2, 04103 Leipzig

The vertical ordering in polyelectrolyte multilayers of Polydiallyldimethylammonium (PDDA) chloride and Sodium polystyrenesulfonate with film thicknesses of 20 to 40 nm has been investigated by means of Neutral Impact Collision Ion Scattering Spectroscopy (NICISS). NICISS allows a model-independent evaluation of concentration depth profiles of all elements in the polyelectrolyte multilayer. By labeling certain polyelectrolyte layers with heavy atom (Ru) probes sufficient contrast has been obtained to visualize and quantify the distribution of these labeled polyelectrolytes throughout the film.

The effect of exposition of the samples to high temperatures and high salt concentrations has been investigated. An increased layer interdiffusion is observed with increasing temperature and increasing salt concentration.

The distribution of small counter ions in the film has also been investigated. PDDA has been deposited with either Chloride or Bromide as a counter ion. The depth profiles show that chloride is located exclusively at the outermost layer. On the other hand bromide is distributed throughout the whole film. The different behavior may be related to the different hydrophobicities of the two species.