SANS study of Block Copolymer Micelles in Supercritical CO_2
Abstract
Small angle neutron scattering measurements, demonstrate the solubilization of a styrene oligomer in block copolymer micelles in supercritical carbon dioxide (SC-CO_2). This observation may be of technological importance. A polydisperse core/shell spherical model of aggregates was used to fit the scattering data, and yields consistent results for a series of copolymers in solution, in which the CO_2-philic (fluorinated) block of the copolymer varied in length by a factor of 3.5, while the CO_2-phobic block length was kept fixed. For this series of diblocks, the aggregation number was found to remain constant at 6 to 7 block copolymer molecules per micelle, in accordance with theoretical expectations. For experiments in which styrene oligomer was added to the block copolymer solutions, virtually all of the oligomer was solubilized in the core of the micelle. In addition, the aggregation number was found to increase with oligomer concentration. These measurements may be useful to test thermodynamic models of micellization and solubilization.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 1996
- Bibcode:
- 1996APS..MAR..M705L