Regensburg 2010 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 18: Interfaces and Thin Films II
CPP 18.8: Vortrag
Dienstag, 23. März 2010, 15:45–16:00, H39
Stress relaxation during polymer brush swelling — Sebastian Lenz1, Adrian Rühm2, Rüdiger Berger1, and •Jochen S. Gutmann1,3 — 1Max-Planck-Institut für Polymerforschung, Ackermannweg 10, D-55128 Mainz (Germany) — 2Max-Planck-Institut für Metallforschung, ZWE FRM-II / N-REX+, Lichtenbergstr. 1, D-85747 Garching bei München (Germany) — 3Institut für physikalische Chemie, Johannes Gutenberg Universität, Jakob-Welder-Weg 10, D-55099 Mainz (Germany)
End-tethered polymer brushes can be used to create switchable surfaces. The properties of such surfaces are dependent on the solvent quality. We focused on the swelling behavior of poly-methyl-methacrylate (PMMA) brushes as a model system. The aim of the presented work was to relate structural brush features in the collapsed/swollen state, such as the brush thickness and the adsorbed solvent fraction, to mechanical properties.
The structure of the polymer brush was measured in situ with Neutron Reflectivity (NR) as a function of solvent quality. Using scaling theories the effective polymer-solvent interaction parameters could be estimated from the NR results.
Preparing the PMMA brush directly on nanomechanical cantilever sensor arrays allowed us to perform surface stress experiments and relate the obtained mechanical results to the results obtained from NR. It was concluded that attractive polymer/polymer interactions relax towards zero reaching theta solvent conditions.