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Restricted diffusion in the regime of the order-to-disorder transition in diblock copolymers: a field gradient NMR study

Fleischer, G. ; Fujara, Franz ; Stühn, Bernd (1993)
Restricted diffusion in the regime of the order-to-disorder transition in diblock copolymers: a field gradient NMR study.
In: Macromolecules, 26 (9)
Artikel, Bibliographie

Kurzbeschreibung (Abstract)

The self-diffusion of diblock copolymers of polystyrene/cis-1,4-isoprene and polyisoprene homopolymers is studied using field gradient nuclear magnetic resonance. The block copolymers are shown to go through their order-to-disorder transition (ODT) at experimentally accessible temperatures. Their phase state is determined using small-angle X-ray scattering. Diffusion in the ordered, lamellar phase is found to be spatially restricted. Fast motion is possible along the lamellae and within a grain. The crossing over the enthalpic barriers between styrene and isoprene domains takes place on a much longer time scale. The ODT does not lead to an abrupt crossover to unrestricted diffusion. Local order remains even above the ODT, and the barriers disappear only gradually.

Typ des Eintrags: Artikel
Erschienen: 1993
Autor(en): Fleischer, G. ; Fujara, Franz ; Stühn, Bernd
Art des Eintrags: Bibliographie
Titel: Restricted diffusion in the regime of the order-to-disorder transition in diblock copolymers: a field gradient NMR study
Sprache: Englisch
Publikationsjahr: April 1993
Titel der Zeitschrift, Zeitung oder Schriftenreihe: Macromolecules
Jahrgang/Volume einer Zeitschrift: 26
(Heft-)Nummer: 9
Kurzbeschreibung (Abstract):

The self-diffusion of diblock copolymers of polystyrene/cis-1,4-isoprene and polyisoprene homopolymers is studied using field gradient nuclear magnetic resonance. The block copolymers are shown to go through their order-to-disorder transition (ODT) at experimentally accessible temperatures. Their phase state is determined using small-angle X-ray scattering. Diffusion in the ordered, lamellar phase is found to be spatially restricted. Fast motion is possible along the lamellae and within a grain. The crossing over the enthalpic barriers between styrene and isoprene domains takes place on a much longer time scale. The ODT does not lead to an abrupt crossover to unrestricted diffusion. Local order remains even above the ODT, and the barriers disappear only gradually.

Fachbereich(e)/-gebiet(e): 05 Fachbereich Physik
05 Fachbereich Physik > Institut für Festkörperphysik (2021 umbenannt in Institut für Physik Kondensierter Materie (IPKM))
Hinterlegungsdatum: 17 Mai 2011 11:06
Letzte Änderung: 28 Mär 2024 15:14
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