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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. and Fujara, F. and Stühn, B. (1993):
Restricted diffusion in the regime of the order-to-disorder transition in diblock copolymers: a field gradient NMR study.
In: Macromolecules, pp. 2340-2345, 26, (9), [Article]

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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.

Item Type: Article
Erschienen: 1993
Creators: Fleischer, G. and Fujara, F. and Stühn, B.
Title: Restricted diffusion in the regime of the order-to-disorder transition in diblock copolymers: a field gradient NMR study
Language: English
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.

Journal or Publication Title: Macromolecules
Volume: 26
Number: 9
Divisions: 05 Department of Physics
05 Department of Physics > Institute for condensed matter physics
Date Deposited: 17 May 2011 11:06
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