COLL 528 |
| A Fery, Federic Dubreuil, Julien Heuvingh, Nils Elsner, and Helmuth Möhwald. Interface department, MPI für Kolloid und Grenzflächenforschung, Am Mühlenberg, Potsdam, D14467, Germany |
| 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 “smart” materials like mechanosensitive capsules that change their mechanical properties in reaction to changes in 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 show how this mechanosensitivity can be used to control microcapsule adhesion properties. |
|
Symposium in Memory of Arthur W. Adamson
2:00 PM-4:40 PM, Thursday, April 1, 2004 Marriott -- Orange County 4, Oral
Division of Colloid and Surface Chemistry |