Fluctuation effects in bulk polymer phase behavior

F. S. Bates, J. H. Rosedale, P. Stepanek, T. P. Lodge, P. Wiltzius, R. Hjelm, G. H. Frederickson

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Bulk polymer-polymer, and block copolymer, phase behaviors have traditionally been interpreted using mean-field theories. Recent small-angle neutron scattering (SANS) studies of critical phenomena in model binary polymer mixtures confirm that non-mean-field behavior is restricted to a narrow range of temperatures near the critical point, in close agreement with the Ginzburg criterion. In contrast, strong derivations from mean-field behavior are evident in SANS and rheological measurements on model block copolymers more than 50°C above the order-disorder transition, which can be attributed to sizeable composition fluctuations. Such fluctuation effects undermine the mean-field assumption, conventionally applied to bulk polymers, and result in qualitative changes in phase behavior, such as the elimination of a thermodynamic stability limit in these materials. The influence of fluctuation effects on block copolymer and binary mixture phase behavior is compared and contrasted in this presentation.

Original languageEnglish (US)
Title of host publicationAmerican Chemical Society, Polymer Preprints, Division of Polymer Chemistry
PublisherPubl by ACS
Pages128
Number of pages1
Volume31
Edition2
StatePublished - Aug 1990
EventPapers presented at the Washington, DC Meeting 1990 of the ACS, Division of Polymer Chemistry - Washington, DC, USA
Duration: Aug 26 1990Aug 31 1990

Other

OtherPapers presented at the Washington, DC Meeting 1990 of the ACS, Division of Polymer Chemistry
CityWashington, DC, USA
Period8/26/908/31/90

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