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@ARTICLE{Brodeck:9076,
author = {Brodeck, M. and Alvarez, F. and Moreno, A.J. and Colmenero,
J. and Richter, D.},
title = {{C}hain motion in nonentangled dynamically asymmetric
polymer blends: {C}omparison between atomistic simulations
of {PEO}/{PMMA} and a generic bead-spring model},
journal = {Macromolecules},
volume = {43},
issn = {0024-9297},
address = {Washington, DC},
publisher = {Soc.},
reportid = {PreJuSER-9076},
pages = {3036 - 3051},
year = {2010},
note = {This research project was supported by the European
Commission NoE SoftComp under contract no.
NMP3-CT-2004-502235 and the "Donostia International Physics
Center." F.A. and J.C. acknowledge support from projects
MAT2007-63681 and IT-436-07 (GV) and the Spanish Ministerio
de Educacion y Ciencia (grant no. CSD2006-53). A.J.M.
acknowledges project 2007-60I021. M.B. thanks NoE SoftComp
for support through the Eurothesis project.},
abstract = {The polymer blend of polyethyleneoxide (PEO) and
polymethylmethacrylate (PMMA) constitutes it miscible blend
of high dynamical asymmetry; that is, the fully miscible
components exhibit a large difference in their
glass-transition temperatures, which are 200 K apart. To get
it deeper understanding of the unusual PEO dynamics in this
system, we have performed a fully atomistic MD simulation.
Here we present all information and results obtained on the
chain self-motion. We present the mean square displacements
and the associated non-Gaussian parameters as a function of
temperature. The associated self-correlation function is
compared thoroughly with experiments. We display it Rouse
analysis and find strongly modified mode friction
coefficients but restoring forces that are identical to the
pure melt. Thereby, the Rouse correlators are strongly
stretched, and the mode number, p, dependence of the
relaxation tithes deviates strongly from the p(-2) Rouse
behavior. We have also carried out simulations of a simple
bead-spring blend, which exhibits the same qualitative
dynamic features of the PEO/PMMA system. This suggests that
such features are not specific of the PEO/PMMA system, but
they arc generic in real polymer blends with strong dynamic
asymmetry. A further important issue was the lest of
different models that have been invoked to explain the
anomalous PEO dynamics. We compare with it generalized
Langevin equation (GLE) approach and with it random Rouse
model dealing with a random distribution of friction
coefficients. In all aspects, the GLE model agrees
qualitatively very well with the results of the fully
atomistic simulations. The random Rouse model may be
considered to be it phenomenological instantaneous
approximation valid for the case where the density
fluctuations of the slow PMMA components arc relaxing much
slower than the relevant PEO dynamics.},
keywords = {J (WoSType)},
cin = {IFF-5 / IFF-4 / Jülich Centre for Neutron Science JCNS
(JCNS) ; JCNS},
ddc = {540},
cid = {I:(DE-Juel1)VDB785 / I:(DE-Juel1)VDB784 /
I:(DE-Juel1)JCNS-20121112},
pnm = {BioSoft: Makromolekulare Systeme und biologische
Informationsverarbeitung / Großgeräte für die Forschung
mit Photonen, Neutronen und Ionen (PNI)},
pid = {G:(DE-Juel1)FUEK505 / G:(DE-Juel1)FUEK415},
shelfmark = {Polymer Science},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000275711300049},
doi = {10.1021/ma902820a},
url = {https://juser.fz-juelich.de/record/9076},
}