Study of the dynamics of poly(ethylene oxide) by combining molecular dynamics simulations and neutron scattering experiments

Brodeck, M.; Colmenero, J.; Unruh, T.; Richter, D.; Juranyi, F.; Holderer, O.; Alvarez, F.; Arbe, A.

doi:10.1063/1.3077858

Journal Article

Study of the dynamics of poly(ethylene oxide) by combining molecular dynamics simulations and neutron scattering experiments

Brodeck, M.FZJ* ; Alvarez, F. ; Arbe, A. ; Juranyi, F. ; Unruh, T. ; Holderer, O.FZJ* ; Colmenero, J. ; Richter, D.FZJ*

2009
American Institute of Physics Melville, NY

The journal of chemical physics 130, 094908 (2009) [10.1063/1.3077858]

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Please use a persistent id in citations: http://hdl.handle.net/2128/18967 doi:10.1063/1.3077858

Abstract: We performed quasielastic neutron scattering experiments and atomistic molecular dynamics simulations on a poly(ethylene oxide) (PEO) homopolymer system above the melting point. The excellent agreement found between both sets of data, together with a successful comparison with literature diffraction results, validates the condensed-phase optimized molecular potentials for atomistic simulation studies (COMPASS) force field used to produce our dynamic runs and gives support to their further analysis. This provided direct information on magnitudes which are not accessible from experiments such as the radial probability distribution functions of specific atoms at different times and their moments. The results of our simulations on the H-motions and different experiments indicate that in the high-temperature range investigated the dynamics is Rouse-like for Q-values below approximate to 0.6 A(-1). We then addressed the single chain dynamic structure factor with the simulations. A mode analysis, not possible directly experimentally, reveals the limits of applicability of the Rouse model to PEO. We discuss the possible origins for the observed deviations.

Keyword(s): J ; molecular dynamics method (auto) ; neutron diffraction (auto) ; polymer melts (auto)

Classification:

Physics, Atomic, Molecular & Chemical

Note: We thank A. C. Genix for experimental help in FOCUS. This work is partially based on experiments performed at the Swiss spallation neutron source SINQ, Paul Scherrer Institute, Villigen, Switzerland. This research project was supported by the European Commission NoE SoftComp under Contract No. NMP3-CT-2004-502235 and the "Donostia International Physics Center." A. A., F. A., and J.C. acknowledge support from Project Nos. MAT2007-63681 and IT-436-07 (GV) and the Spanish Ministerio de Educacion y Ciencia (Grant No. CSD2006-53).

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Appears in the scientific report 2009

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OpenAccess