Summary

SANS investigations of individual polymer chains and supramolecular structures have verified the high solubility of amorphous fluoropolymers in CO2, as well as the formation of micelles by block copolymers when CO2 is a preferential solvent for one of the blocks. In addition, the results clearly show that the micellar cores are capable of solubilizing CO2-insoluble material. A transition from unimers to aggregates occurs as a function of pressure, thus demonstrating that solvent strength is easily tunable with changes in solvent density, offering an unprecedented control over the solubility. The CMD constitutes a new concept in colloid and surface chemistry. The self-assembly of molecules in condensed phases is a ubiquitous phenomenon found in many biological structures, as well as in systems of interest to materials, colloid and surface science. These experiments indicate that neutron scattering has the potential to give the same level of microstructural insight into individual polymer molecules (unimers) and colloidal aggregates (micelles) in supercritical CO2 that it has provided in the condensed state and in aqueous media.

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