Regensburg 2010 – wissenschaftliches Programm

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SYMR: Symposium Nuclear Magnetic Resonance: from Applications in Condensed-Matter Physics to New Frontiers

SYMR 2: Poster: Nuclear Magnetic Resonance - Frontiers and Applications

SYMR 2.7: Poster

Montag, 22. März 2010, 16:30–18:00, Poster C

Chain Dynamics of Polymers Confined to Ordered Nanoporous Alumina MembranesCornelius Franz1, •Salim Ok2, Fabián Vaca Chávez1, Martin Steinhart2, 3, and Kay Saalwächter11Institut für Physik, Betty-Heimann-Str.7, 06120 Halle, Germany — 2Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany — 3Institut für Chemie, Barbarastr. 7, Universität Osnabrück, 49069 Osnabrück, Germany

Ordered anodic aluminum oxide (AAO) membranes with cylindrical 20-400nm pores are ideal inorganic model components that allow studying polymeric interphases and confinement effects in nanocomposites. Advanced NMR techniques enable characterization of polymer chain dynamics in detail. We report the study of polybutadiene (PB) melts infiltrated into AAO by means of transverse relaxometry (T2) as a qualitative indicator for changes in chain dynamics, and by multiple-quantum NMR for more detailed insights.

PB forms solid nanorods in the nanopores of the AAO. Filling kinetics experiments revealed the conditions under which the pore volume is completely filled and equilibrium is reached. At non-equilibrium stages, we observed strong deviations from the bulk-like entanglement-induced chain ordering, including much increased chain order and an inhomogeneous response, indicating possible layering effects. After the infiltration equilibrium was reached, the behavior was more homogeneous, but still significantly higher local chain order was detected. Moreover, MQ NMR data indicate a shift of Tg. All observed effects became more pronounced upon reduction of the pore diameter.

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