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@ARTICLE{Brodeck:19755,
author = {Brodeck, M. and Alvarez, F. and Colmenero, J. and Richter,
D.},
title = {{S}ingle {C}hain {D}ynamic {S}trucutre {F}actor of
{P}oly(ethylene oxide) in {D}ynamically {A}symmetric
{B}lends with {P}oly(methyl methacrylate). {N}eutron
{S}cattering and {M}olecular {D}ynamics {S}imulations},
journal = {Macromolecules},
volume = {45},
issn = {0024-9297},
address = {Washington, DC},
publisher = {Soc.},
reportid = {PreJuSER-19755},
pages = {536 - 542},
year = {2012},
note = {This research project has been supported by the European
Commission NoE SoftComp, Contract NMP3-CT-2004-502235, and
the "Donostia International Physics Center". J.C. and F.A.
acknowledge support from the projects MAT2007-63681 and
IT-436-07 (GV).},
abstract = {We have investigated the dynamically asymmetric polymer
blend composed of short (M-n approximate to 2 kg/mol)
poly(ethylene oxide) (PEO) and poly(methyl methacrylate)
(PMMA) chains focusing on the collective dynamics of the
fast PEO component. Using neutron spin-echo (NSE)
spectroscopy, the single chain dynamic structure factor of
PEO was investigated and compared to results from molecular
dynamics simulations. After a successful validation of the
simulations, a thorough analysis of the RPA approximation
reveals the composition of the experimentally measured total
scattering signal S(Qt). Using the simulations, we show and
calculate two contributions: (1) the relaxation of
hydrogenated PEO against deuterated PLO, yielding the single
chain dynamic structure factor of P:EO, and (2) the
relaxation of the PEO component against the,PMMA matrix For
the short chains presented here the second contribution
shows a significant decay at higher temperatures While it
was previously shown that, in the case of long chains, no
relaxation is found. This difference is related to a
decrease of the glass transition temperature which takes
place with decreasing chain length. In a second step we
analyze the approximations that are used when calculating
the single chain dynamic structure factor using the Rouse
model. For a system like pure PEO, where the dynamics follow
the predicted Rouse behavior, excellent agreement is
achieved. In the case of PEO in PMMA, however, the slow PMMA
matrix strongly influences the PEO dynamics. As a result,
the distribution functions show a strong non-Gaussianity,
and the calculation of S(Qt) using the Rouse approximation
fails even considering nonexponential Rouse mode
correlators.},
keywords = {J (WoSType)},
cin = {ICS-1 / Jülich Centre for Neutron Science JCNS (JCNS) ;
JCNS / JCNS-1 / JCNS (München) ; Jülich Centre for Neutron
Science JCNS (München) ; JCNS-FRM-II},
ddc = {540},
cid = {I:(DE-Juel1)ICS-1-20110106 / I:(DE-Juel1)JCNS-20121112 /
I:(DE-Juel1)JCNS-1-20110106 /
I:(DE-Juel1)JCNS-FRM-II-20110218},
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},
experiment = {EXP:(DE-MLZ)J-NSE-20140101},
shelfmark = {Polymer Science},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000298905000057},
doi = {10.1021/ma2016634},
url = {https://juser.fz-juelich.de/record/19755},
}