0000000000347348
AUTHOR
Pappannan Thiyagarajan
Kinetics of block-copolymer aggregation in super critical CO2
Small angle X-ray and neutron scattering (SAXS and SANS) are used to obtain structural information on the aggregation behavior of block-copolymers dissolved in supercritical CO2. The SANS technique is used to provide a detailed structural model for the micellar aggregates, which form below the critical micellization density (CMD), that we defined in our previous work. The SAXS technique (with a synchrotron source) is used to provide the first experimental information concerning the kinetic features of both formation and decomposition of such aggregates as soon as pressure jumps are applied to the solutions across the CMD. 2002 Elsevier Science B.V. All rights reserved.
A combined small-angle neutron and X-ray scattering study of block copolymers micellisation in supercritical carbon dioxide
Small angle neutron and X-ray scattering (SANS and SAXS) are used to investigate the monomer–aggregate transition of fluorocarbon–hydrocarbon diblock copolymers in supercritical carbon dioxide. SANS data are analyzed using a polydisperse sphere core–shell model. Synchrotron SAXS data have been collected by profiling the pressure at different temperatures, and critical micellization densities have been obtained for a series of diblock solutions. Finally pressure jump experiments, combined with synchrotron SAXS, have revealed two steps in the dynamics of the formation of the aggregates.