Hoffmann, A. ; Koch, T. ; Stühn, B. (1993)
Effect of the disorder-to-order transition in diblock copolymers on the segmental dynamics: a study using depolarized photon correlation spectroscopy.
In: Macromolecules, 26 (26)
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
Depolarized light scattering has been applied to study the anisotropy fluctuations in a series of polystyrene/polyisoprene diblock copolymers. This method is selective for the dynamics of the polystyrene block. The molecular weights of the block copolymers (10500-20800) were chosen such that the microphase separation transition (MST) occurs at temperatures which are experimentally accessible with photon correlation spectroscopy. Small-angle X-ray scattering (SAXS) was used to identify the disordered regime, the fluctuation-controlled transition regime, and the ordered state. The relaxation time spectrum in the disordered state is similar to that of bulk polystyrene. Concentration fluctuations increasingly broaden the spectrum and lead to a bimodal shape. Close to the MST the spectrum becomes dominated by a slow, nearly single exponential contribution. Comparison with the SAXS results suggests that this splitting of the relaxation time spectrum can be related to chain stretching.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 1993 |
| Autor(en): | Hoffmann, A. ; Koch, T. ; Stühn, B. |
| Art des Eintrags: | Bibliographie |
| Titel: | Effect of the disorder-to-order transition in diblock copolymers on the segmental dynamics: a study using depolarized photon correlation spectroscopy |
| Sprache: | Englisch |
| Publikationsjahr: | Dezember 1993 |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Macromolecules |
| Jahrgang/Volume einer Zeitschrift: | 26 |
| (Heft-)Nummer: | 26 |
| Kurzbeschreibung (Abstract): | Depolarized light scattering has been applied to study the anisotropy fluctuations in a series of polystyrene/polyisoprene diblock copolymers. This method is selective for the dynamics of the polystyrene block. The molecular weights of the block copolymers (10500-20800) were chosen such that the microphase separation transition (MST) occurs at temperatures which are experimentally accessible with photon correlation spectroscopy. Small-angle X-ray scattering (SAXS) was used to identify the disordered regime, the fluctuation-controlled transition regime, and the ordered state. The relaxation time spectrum in the disordered state is similar to that of bulk polystyrene. Concentration fluctuations increasingly broaden the spectrum and lead to a bimodal shape. Close to the MST the spectrum becomes dominated by a slow, nearly single exponential contribution. Comparison with the SAXS results suggests that this splitting of the relaxation time spectrum can be related to chain stretching. |
| Fachbereich(e)/-gebiet(e): | 05 Fachbereich Physik > Institut für Festkörperphysik (2021 umbenannt in Institut für Physik Kondensierter Materie (IPKM)) 05 Fachbereich Physik |
| Hinterlegungsdatum: | 26 Feb 2010 13:54 |
| Letzte Änderung: | 05 Mär 2013 09:32 |
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