Glassy Dynamics of Simulated Polymer Melts: Coherent Scattering and Van Hove Functions Part II: Dynamics in the alpha-Relaxation Regime

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dc.creatorAichele, M.
dc.creatorBaschnagel, J.
dc.date2001-03-20
dc.date.accessioned2026-07-07T02:40:47Z
dc.date.available2026-07-07T02:40:47Z
dc.descriptionWhereas the first part of this paper dealt with the relaxation in the beta-regime, this part investigates the final (alpha) relaxation of a simulated polymer melt consisting of short non-entangled chains above the critical temperature Tc of mode-coupling theory (MCT). We monitor the intermediate incoherent as well as the coherent chain and coherent melt scattering functions over a wide range of wave numbers q. Upon approaching Tc the coherent alpha-relaxation time of the melt increases strongly close to the maximum of the static structure factor of the melt. At q corresponding to the radius of gyration of the chain the melt relaxation time exhibits another maximum. The temperature dependence of the relaxation times is well described by a power-law with a q-dependent exponent in an intermediate temperature range. The time-temperature superposition principle of MCT is clearly bourne out in the whole range of wave numbers. An analysis of the alpha-decay using Kohlrausch-Williams-Watts (KWW) functions reveals that the collective melt KWW-stretching exponent and KWW-relaxation times are modulated with the structure factor. Furthermore, both incoherent and coherent KWW-times approach the large-q prediction of MCT at q comparable to the maximum of the structure factor. At small q a power law with exponent -3 is found for the coherent chain KWW-times similar to that of recent experiments.
dc.description12 pages, 8 figures. LaTeX2e article with EPJ style files. Accepted for publication in EPJ E
dc.identifierhttps://arxiv.org/abs/cond-mat/0103416
dc.identifierhttp://arxiv.org/abs/cond-mat/0103416
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/17503
dc.subjectSoft Condensed Matter
dc.subjectDisordered Systems and Neural Networks
dc.titleGlassy Dynamics of Simulated Polymer Melts: Coherent Scattering and Van Hove Functions Part II: Dynamics in the alpha-Relaxation Regime
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