Molecular observation of contour-length fluctuations limiting topological confinement in polymer melts.
In order to study the mechanisms limiting the topological chain confinement in polymer melts, we have performed neutron-spin-echo investigations of the single-chain dynamic-structure factor from polyethylene melts over a large range of chain lengths. While at high molecular weight the reptation model is corroborated, a systematic loosening of the confinement with decreasing chain length is found. The dynamic-structure factors are quantitatively described by the effect of contour-length fluctuations on the confining tube, establishing this mechanism on a molecular level in space and time.
Wischnewski
A
A
Institut für Festkörperforschung, Forschungszentrum Jülich, D-52425 Jülich, Germany.
Monkenbusch
M
M
Willner
L
L
Richter
D
D
Likhtman
A E
AE
McLeish
T C B
TC
Farago
B
B