Design of Nonionic Surfactants for Supercritical Carbon Dioxide
Interfacially active block copolymer amphiphiles have been synthesized and their self-assembly into micelles in supercritical carbon dioxide (CO2) has been demonstrated with small-angle neutron scattering (SANS). These materials establish the design criteria for molecularly engineered surfactants that can stabilize and disperse otherwise insoluble matter into a CO2 continuous phase. Polystyrene-b-poly(1,1-dihydroperfluorooctyl acrylate) copolymers self-assembled into polydisperse core-shell-type micelles as a result of the disparate solubility characteristics of the different block segments in CO2. These nonionic surfactants for CO2 were shown by SANS to be capable of emulsifying up to 20 percent by weight of a CO2-insoluble hydrocarbon into CO2. This result demonstrates the efficacy of surfactant-modified CO2 in reducing the large volumes of organic and halogenated solvent waste streams released into our environment by solvent-intensive manufacturing and process industries.
McClain
JB
J. B. McClain, D. E. Betts, D. A. Canelas, E. T. Samulski, J. M. DeSimone, Department of Chemistry, University of North Carolina, CB 3290, Venable and Kenan Laboratories, Chapel Hill, NC 27599, USA. J. D. Londono, H. D. Cochran, G. D. Wignall, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA. D. Chillura-Martino and R. Triolo, Departimento di Chimica Fisica, University of Palermo, 90123 Palermo, Italy.
Betts
DE
Canelas
DA
Samulski
ET
DeSimone
JM
Londono
JD
Cochran
HD
Wignall
GD
Chillura-Martino
D
Triolo
R