Regensburg 2004 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 13: SYMPOSIUM: Understanding and Controlling Complex Structures: From Synthetic Polymers to Biomaterials I

CPP 13.5: Vortrag

Dienstag, 9. März 2004, 11:15–11:30, H 37

Quantifying and Controlling the Mechanical properties of polyelectrolyte multilayer capsules: Towards mechanosensitive microcapsules — •Andreas Fery, Frederic Dubreuil, Nils Elsner, Julien Heuvingh, and Melmuth Möwald — MPI for Colloids and Interfaces Golm

Quantifying the mechanical properties of microcapsules is of interest for both a basic science understanding of those systems and for their applications. Control of the mechanical properties could lead to new No-dqsmartNo-dq materials like No-dqmechanosensitiveNo-dq capsules that change their mechanical properties in reaction depending on their environment.

In this context, hollow capsules made from polyelectrolyte multilayers are promising, because they can be produced with well defined geometry, wall thickness and from various materials.

We use AFM force-spectroscopy and optical microscopy to directly probe the deformability of individual microcapsules in solvent environment. Using continuum mechanics models, we can derive the elastic constants of the wall material. We find that the Youngs-modulus of microcapsules made from PAH (Polyallylamine)/PSS (Polystyrenesulfonate) is depending on the solution salt concentration and pH. We discuss the effects in terms of simple molecular pictures and present how this mechanosensitivity can be used to control microcapsule adhesion properties.