Non-exponential Rouse correlators and generalized magnitudes probing chain dynamics

Inspired by the generalized Langevin equation (GLE) formalism with some approximations, we have proposed a method to generalize the Rouse expression of the magnitudes probing chain dynamics, taking into account the non-exponential character of the Rouse mode correlators. In this way, generalized exp...

Full description

Saved in:
Bibliographic Details
Published in:Journal of non-crystalline solids 2015-01, Vol.407, p.302-308
Main Author: Colmenero, J.
Format: Article
Language:English
Subjects:
Chain dynamics
Correlators
Density
Dielectric spectroscopy
Dynamical systems
Frequency domains
Mathematical analysis
Molecular dynamics
Molecular dynamics simulations
Neutron scattering
Polymer blends
Polymer dynamics
Polymethyl methacrylates
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Inspired by the generalized Langevin equation (GLE) formalism with some approximations, we have proposed a method to generalize the Rouse expression of the magnitudes probing chain dynamics, taking into account the non-exponential character of the Rouse mode correlators. In this way, generalized expressions for the incoherent neutron scattering function and for the End-to-End relaxation – which give rise in the frequency domain to the dielectric ‘normal mode’ relaxation – have been obtained. These magnitudes have been checked by means of fully atomistic molecular dynamics (MD) simulations corresponding to pure poly(ethylene oxide) (PEO) and to PEO in an asymmetric blend with poly(methyl methacrylate) (PMMA). Moreover, the results obtained also seem to give support to the unified scenario recently proposed for explaining the non-exponential relaxation of the long-wavelength Rouse modes in polymer systems in terms of the effect of density fluctuations (α-process) on chain dynamics. •We address the origin of nonexponential Rouse correlators in the GLE formalism.•Generalized expressions for magnitudes probing chain dynamics are proposed.•These expressions are validated by MD-simulations of polymers.
ISSN:0022-3093
1873-4812
DOI:10.1016/j.jnoncrysol.2014.09.033