This title appears in the Scientific Report :
2008
Please use the identifier:
http://dx.doi.org/10.1021/jp807035z in citations.
Cooperative dynamics in homopolymer melts: a comparision of theoretical predictions with neutron spin echo experiments
Cooperative dynamics in homopolymer melts: a comparision of theoretical predictions with neutron spin echo experiments
We present a comparison between theoretical predictions of the generalized Langevin equation for cooperative dynamics (CDGLE) and neutron spin echo data of dynamic structure factors for polyethylene melts. Experiments cover an extended range of length and time scales, providing a compelling test for...
Saved in:
Personal Name(s): | Zamponi, M. |
---|---|
Wischnewski, A. / Monkenbusch, M. / Willner, L. / Richter, D. / Falus, P. / Farago, B. / Guenza, M.G. | |
Contributing Institute: |
JCNS; JCNS Streumethoden; IFF-4 Neutronenstreuung; IFF-5 |
Published in: |
The @journal of physical chemistry |
Imprint: |
Washington, DC
Soc.
2008
|
Physical Description: |
16220 - 16229 |
PubMed ID: |
19072142 |
DOI: |
10.1021/jp807035z |
Document Type: |
Journal Article |
Research Program: |
Großgeräte für die Forschung mit Photonen, Neutronen und Ionen (PNI) Kondensierte Materie |
Series Title: |
Journal of Physical Chemistry B
112 |
Subject (ZB): | |
Publikationsportal JuSER |
We present a comparison between theoretical predictions of the generalized Langevin equation for cooperative dynamics (CDGLE) and neutron spin echo data of dynamic structure factors for polyethylene melts. Experiments cover an extended range of length and time scales, providing a compelling test for the theoretical approach. Samples investigated include chains with increasing molecular weights undergoing dynamics across the unentangled to entangled transition. Measured center-of-mass (com) mean-square displacements display a crossover from subdiffusive to diffusive dynamics. The generalized Langevin equation for cooperative dynamics relates this anomalous diffusion to the presence of the interpolymer potential, which correlates the dynamics of a group of slowly diffusing molecules in a dynamically heterogeneous liquid. Theoretical predictions of the subdiffusive behavior, of its crossover to free diffusion, and of the number of macromolecules undergoing cooperative motion are in quantitative agreement with experiments. |