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

Autor:	G. Fleischer, B. Stuehn, F. Fujara
Rok vydání:	1993
Předmět:	Self-diffusion Polymers and Plastics Field (physics) Scattering Diffusion Organic Chemistry Inorganic Chemistry chemistry.chemical_compound chemistry Lamellar phase Chemical physics Restricted Diffusion Polymer chemistry Materials Chemistry Copolymer Polystyrene
Zdroj:	Macromolecules. 26:2340-2345
ISSN:	1520-5835 0024-9297
DOI:	10.1021/ma00061a029
Popis:	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.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::3e4560623baa3ec6c3668d0d4ed3341a https://doi.org/10.1021/ma00061a029 Zobrazit plný text záznamu