Dresden 2003 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 20: POSTER A

CPP 20.43: Poster

Montag, 24. März 2003, 19:00–21:00, ZEU/250

Adhesion of shells on flat substrates — •Nils Elsner, Andreas Fery, and Helmut Moehwald — Max-Planck-Instiut fuer Kolloid- und Grenzflaechenforschung, 14476 Golm

The interaction of polyelectrolyte capsules composed from PAH and PSS with a glass surface in water was studied by Reflection Interference Contrast Microscopy (RICM) measurements. It was found, that capsules with negatively charged Polystyrenesulfonate as the outermost layer adhere to glass, which was covered with positively charged Polyethylenimine, while no adhesive interactions were detected on negatively charged substrates.

In case of adhesion, we find that the shells develop circular adhesion discs on the substrate but remain spherical outside the adhesion zone. Typical radii of the adhesion areas are in the range of several microns for shells of 10-20 microns. The radius of the adhesion disc depends strongly on both the shell radius and on the shell thickness that was obtained from AFM measurements of dried shells. We present a simple model based on Landau shell theory that can explain the observed radius dependency.