Dresden 2003 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 22: POSTER C

CPP 22.50: Poster

Donnerstag, 27. März 2003, 12:00–14:00, ZEU/250

Swelling of adsorbed polyelectrolyte multilayers: towards a better understanding of the internal structure — •John Eric Wong and Regine von Klitzing — Stranski-Laboratorium für Physikalische und Theoretische Chemie,TU Berlin, Strasse des 17. Juni 112, 10623 Berlin, Germany

The polymer films presented in this study were made by alternate adsorption of polyanions and polycations from aqueous solution onto solid substrates (Silicon, glass) using the layer-by-layer method developed in the early 1990s by Decher et al. Although there have been intensive studies on the different parameters, like the polymer charge density and the ionic strength influencing film formation by this technique, there have been relatively fewer interests in the hydration of such polyelectrolyte multilayers. In the present work the equilibrium film thickness was measured by ellipsometry and X-ray reflectometry at different relative atmospheric humidities. We found that the amount of water absorbed by the polymer film increases with increasing film thickness, but the net percentage of water absorbed decreases after reaching a maximum for a certain number of layers. These findings enable us to have a better understanding of the internal structure of the polyelectrolyte multilayers as we shall attempt to explain our results.