M. Hofmann, A. Herrmann, S. Ok, C. Franz, D. Kruk, K. Saalwächter, E. A.
Polymer Dynamics of Polybutadiene in Nanoscopic Confinement As
Revealed by Field Cycling 1H NMR.
Macromolecules 44, xxx (2011). DOI 10.1021/ma2002504.
Applying electronic field cycling 1H NMR
relaxometry we have investigated the segmental and collective dynamics of
polybutadiene (M = 87 kDa) in bulk and in self-ordered aluminium oxide
membranes with pore channel diameters of 60 nm and 20 nm over a broad
temperature range (200 - 400 K). Although the confinement size is larger than
the Flory radius, confinement effects have been found. The susceptibility
spectrum of the collective polymer dynamics remains essentially the same in the
accessible frequency range, however, the time scale of polymer dynamics slows
down whereas that of segment dynamics remains unchanged. On the basis of the
results we offer an alternative explanation of a phenomenon referred to as the
corset effect introduced by Kimmich and co-workers.