Dresden 2003 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
CPP: Chemische Physik und Polymerphysik
CPP 1: Polymerschmelzen
CPP 1.11: Vortrag
Montag, 24. März 2003, 12:30–12:45, ZEU/160
NSE study on the influence of contour length fluctuations on the reptation process — •M. Zamponi1, M. Monkenbusch1, D. Richter1, L. Willner1, A. Wischnewski1, B. Farago2, A.E. Likhtman3, and T.C.B. McLeish3 — 1Institut für Festkörperforschung, Forschungszentrum Jülich, Jülich, Germany — 2Institut Laue-Langevin, Grenoble, France — 3University of Leeds, Leeds, United Kingdom
High resolution neutron spin echo (NSE) spectroscopy has been used to measure the dynamic structure factor of polyethylene (PE) melt in the entangled regime. As it has been shown recently [1], with decreasing chain length a loosening of confinement due to contour length fluctuations can be observed.
Now by using center labeled PE chains the reptation process
without such end effects has been explored. The center label
length has been varied to see the influence of the contour length
fluctuations on the disentanglement process.
For longer chains, the dynamic structure factor shows a well
defined plateau, the chain center remains confined in a virtual
tube. The data is well described by the pure reptation model, the
resulting tube diameter is consistent with previous results.
For shorter chains, the same effect is visible but not as
pronounced. The dynamic structure factor shows a faster decay as
expected. This might be explained with the onset of constraint
release.
[1] Wischnewski et al., PRL 88, 058301 (2002)