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CPP: Chemische Physik und Polymerphysik

CPP 20: POSTER A

CPP 20.35: Poster

Monday, March 24, 2003, 19:00–21:00, ZEU/250

MECHANICAL PROPERTIES OF HOLLOW CAPSULES — •Frederic Dubreuil, Nils Elsner, Andreas Fery, and Helmuth Moehwald — Max Planck Institut fuer Kolloide und Grenflaechen

We are investigating the mechanical properties of hollow polyelectrolyte shells of colloidal dimensions trapped on flat substrates. Polyelectrolyte shells that are produced by a stepwise adsorption of polyelectrolyte-monolayers on colloids and subsequent dissolution of the core are a promising model system for the realisation of artificial cells and can be used as microreactors. The mechanical behaviour of these shells can be tuned to reach the desired property both by choosing different polyelectrolyte combinations for the layer buildup and, for a given material, by adjusting the layer thickness. We combine force spectroscopy measurements using AFM to measure forces necessary for the shell deformation and Reflection Interference Contrast microscopy to visualise the induced shell deformation simultanously. Thus we can relate the deformation of the capsule to the applied force. The elasticity (Young modulus) and plasticity (limit of the elastic regime) of the capsules are studied as a function of the structural parameters (wall thickness and composition).