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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 17: Interfaces and Thin Films I

CPP 17.2: Vortrag

Dienstag, 23. März 2010, 10:00–10:15, H39

Soft Colloidal Probe AFM - A New Method for the Investigation of Adhesion and Contact of Soft Surfaces — •Johann Erath, Stephan Schmidt, Petra Zippelius, and Andreas Fery — Universität Bayreuth, 95440 Bayreuth, Germany

We introduce a novel approach for AFM based adhesion measurements which combines the advantages of the JKR-apparatus and AFM-force-spectroscopy. We create a defined microscopic contact by using a soft colloidal probe made of Polydimethylsiloxane. This allows in-situ determination of the contact area as a function of applied load and elastic properties of the sytem. Hence, similar to the JKR-apparatus, adhesion energies can be determined from a fit of a whole set of data of well-defined contact areas and load forces. Besides tests on model systems, where we can clearly characterize contributions of capillary forces, hydration forces and hydrophobic interactions, this technique makes a broader range of systems and scientific issues accessible. In this presentation we focus on the lower limit of elastic constants, where the probes will approach typical values for soft biological materials like cells and thus provide elasticity matched partners for adhesion measurements.