Small angle neutron scattering from polymers in supercritical carbon dioxide


Journal Article (Review)

Above its critical point, carbon dioxide forms a supercritical (SC) solvent which promises to be an environmentally responsible replacement for the organic solvents currently used in polymer synthesis and processing. CO2–soluble molecules (e.g. tluoropolymers) have been charkterized using small angle neutron scattering (SANS). By analogy with light and small-angle X–ray scattering (SAXS) experiments on polymers in dilute solution, the radius of gyration (Rg), molecular weight (MW) and second osmotic virial coefficient (A,) are determined from SANS experiments in SC–CO2. However, many polymers do not dissolve in this medium and in order to promote the synthesis of such materials, a range of amphiphilic block copolymers has been developed. These molecules function as surfactants or emulsifying agents to solubilize the CO2–phobic polymers. In the case of diblock copolymers in SC–CO2, aggregation occurs when the solvent is preferential for one of the blocks, and SANS allows the size and shape of the aggregates (micelles) to be determined. Illustrative examples of these studies are given and neutron scattering promises to give the same level of insight into polymers and amphiphiles in supercritical media that it has provided in the condensed state and in aqueous systems. © 1999, Taylor & Francis Group, LLC.

Full Text

Duke Authors

Cited Authors

  • Londono, JD; Wignall, GD; Cochran, HD; McClain, JB; Betts, DE; Canelas, DA; Desimone, JM; Samulski, ET; Triolo, R

Published Date

  • January 1, 1999

Published In

Volume / Issue

  • 10 / 2

Start / End Page

  • 10 - 15

Electronic International Standard Serial Number (EISSN)

  • 1931-7352

International Standard Serial Number (ISSN)

  • 1044-8632

Digital Object Identifier (DOI)

  • 10.1080/10448639908233669

Citation Source

  • Scopus