Regensburg 2002 – wissenschaftliches Programm

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SYPF: Struktur und Dynamik in dünnen Polymerfilmen

SYPF 2: Poster Session

SYPF 2.31: Poster

Donnerstag, 14. März 2002, 09:00–18:00, Poster B

Adhesion energy between polyelectrolyte-coated surfaces investigated with AFM — •Vera Bosio and Andreas Fery — MPIKG-Grenzflaechenabteilung, D-14424 Potsdam

We investigate the adhesion of colloidal particles in the micrometer range on flat substrates (silicone wafers, glass). Both particles and substrates are coated by the same polyelectrolyte multilayers, using the layer-by-layer technique. The coated particle is glued to a tipless AFM cantilever and acts as the AFM tip. We measure the AFM force-distance curve in an aqueous environment and vary the pH in-situ. We can monitor the adhesion energy as functions of the pH, the salt concentration, the type of polyelectrolytes, as well as the number of assembled layers. Thus effective surface pKs can be determined and the influence of other layers than the topmost in adhesion processes can be quantified. In order to better understanding the layer architecture and the interaction between the PE adjacent layers, we also measure how the force depends on the contact time between sample and probe.