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Light-scattering study of fluctuations in concentration, density, and local anisotropy in polystyrene-dioxane mixtures

Koch, T. ; Strobl, G. ; Stühn, B. (1992)
Light-scattering study of fluctuations in concentration, density, and local anisotropy in polystyrene-dioxane mixtures.
In: Macromolecules, 25 (23)
Article

Abstract

Static and dynamic light scattering was applied in a comprehensive study of the different modes of relaxatory motion in polystyrene-dioxane mixtures, comprising the whole range of different compositions from dilute solution to plasticized melts. For the analysis of data measured in the presence of the nearly elastic anomalous excess scattering usually encountered in concentrated solutions and the melt, a generalized Siegert relation was used. Analysis of depolarized dynamic scattering data obtained for the PS-rich mixtures indicates a simple Vogel-Fulcher temperature dependence for the relaxation rates of the anisotropy fluctuations with T(g) as the only relevant parameter. The dynamics observed in polarized scattering continuously changes its character, being dominated at low temperatures and high concentrations by density fluctuations and in the limit of high temperatures and low concentrations by concentration fluctuations. Density and anisotropy fluctuations show identical relaxation rates.

Item Type: Article
Erschienen: 1992
Creators: Koch, T. ; Strobl, G. ; Stühn, B.
Type of entry: Bibliographie
Title: Light-scattering study of fluctuations in concentration, density, and local anisotropy in polystyrene-dioxane mixtures
Language: English
Date: November 1992
Journal or Publication Title: Macromolecules
Volume of the journal: 25
Issue Number: 23
Abstract:

Static and dynamic light scattering was applied in a comprehensive study of the different modes of relaxatory motion in polystyrene-dioxane mixtures, comprising the whole range of different compositions from dilute solution to plasticized melts. For the analysis of data measured in the presence of the nearly elastic anomalous excess scattering usually encountered in concentrated solutions and the melt, a generalized Siegert relation was used. Analysis of depolarized dynamic scattering data obtained for the PS-rich mixtures indicates a simple Vogel-Fulcher temperature dependence for the relaxation rates of the anisotropy fluctuations with T(g) as the only relevant parameter. The dynamics observed in polarized scattering continuously changes its character, being dominated at low temperatures and high concentrations by density fluctuations and in the limit of high temperatures and low concentrations by concentration fluctuations. Density and anisotropy fluctuations show identical relaxation rates.

Divisions: 05 Department of Physics > Institute for condensed matter physics (2021 merged in Institute for Condensed Matter Physics)
05 Department of Physics
Date Deposited: 26 Feb 2010 13:45
Last Modified: 05 Mar 2013 09:32
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