Comparison of the Behavior of Polymers in Supercritical Fluids and Organic Solvents Via Small Angle Neutron Scattering
Small-angle neutron scattering has been used to study the effect of temperature and pressure on the phase behavior of semidilute solutions of polymers dissolved in organic and supercritical solvents. Above the theta temperature (To), these systems exhibit a ''good solvent'' domain, where the molecules expand beyond the unperturbed dimensions in both organic solvents and in COZ. However, this transition can be made to occur at a critical ''theta pressure'' (PO) in CO2 and this represents a new concept in the physics of polymer-solvent systems. For T < To, and P < Po, the system enters the ''poor solvent'' domain where diverging concentration fluctuations prevent the chains from collapsing and allow them to maintain their unperturbed dimensions.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (US)
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 768840
- Report Number(s):
- P00-106700; TRN: US0100349
- Resource Relation:
- Conference: XIth International Conference on Small-Angle Scattering, Long Island, NY (US), 05/17/1999--05/20/1999; Other Information: PBD: 17 May 1999
- Country of Publication:
- United States
- Language:
- English
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