title: Compact structure and non-Gaussian dynamics of ring polymer melts.
abstract: We present a neutron scattering analysis of the structure and dynamics of PEO polymer rings with a molecular weight 2.5 times higher than the entanglement mass. The melt structure was found to be more compact than a Gaussian model would suggest. With increasing time the center of mass (c.o.m.) diffusion undergoes a transition from sub-diffusive to diffusive behavior. The transition time agrees well with the decorrelation time predicted by a mode coupling approach. As a novel feature well pronounced non-Gaussian behavior of the c.o.m. diffusion was found that shows surprising analogies to the cage effect known from glassy systems. Finally, the longest wavelength Rouse modes are suppressed possibly as a consequence of an onset of lattice animal features as hypothesized in theoretical approaches.
authors.affiliation: Jülich Centre for Neutron Science JCNS (JCNS-1) and Institute for Complex Systems (ICS), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany. a.bras@fz-juelich.de.
authors.forename: Ana R
authors.initials: AR
authors.lastname: Brás
authors.forename: Sebastian
authors.initials: S
authors.lastname: Goossen
authors.forename: Margarita
authors.initials: M
authors.lastname: Krutyeva
authors.forename: Aurel
authors.initials: A
authors.lastname: Radulescu
authors.forename: Bela
authors.initials: B
authors.lastname: Farago
authors.forename: Jürgen
authors.initials: J
authors.lastname: Allgaier
authors.forename: Wim
authors.initials: W
authors.lastname: Pyckhout-Hintzen
authors.forename: Andreas
authors.initials: A
authors.lastname: Wischnewski
authors.forename: Dieter
authors.initials: D
authors.lastname: Richter
mesh_terms: D004058:Diffusion; D009682:Magnetic Resonance Spectroscopy; D033363:Neutron Diffraction; D011092:Polyethylene Glycols / Q000737:chemistry*; D053838:Scattering, Small Angle
chemical_list: D011092:Polyethylene Glycols