Berlin 2015 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 11: Nanoparticles and Composite Materials II (joint CPP/BP)

BP 11.2: Vortrag

Montag, 16. März 2015, 15:15–15:30, C 243

Dynamics of polymers in composites — •Ulrich Scheler — Leibniz-Institut für Polymerforschung Dresden e.V.

Magnetic resonance is applied to study the dynamics of polymers interacting with inorganic solid surfaces. The dynamics of polymers over a wide range of correlation times is determined using magnetic resonance relaxation experiments for the investigation of systems in contact with solids and inorganic materials. In highly dispersed systems, these are nanoparticles coated with thin films have been investigated. Measurement of T2 or T1rho is ideally suited for the dynamics of chain segments, which is mostly affected by the interaction with the solid surface. Because of sensitivity issues only proton NMR signals have been detected. In order to obtain sufficient chemical resolution for instance to exclude solvent signals in swelling experiments high-resolution solid-state and NMR based on CRAMPS has been applied. These line narrowing techniques permit the selection or suppression of the solvent signal and thus one can focus on the polymer dynamics. It is seen, that there is much stronger motion and dynamics and putting the brushes compared to polymers of the same molecular weight. To investigate that further dedicated techniques for the selective excitations at the interface part based on magnetization transfer from the inorganic particle to the polymer has been applied. Spin-labels on polyelectrolytes permit the selective study of the dynamics of the polymer in the vicinity of the label. Because of the high sensitivity of EPR dynamics of individual layers in a multilayer system can be studied.