Ej. Singley et al., PHASE-BEHAVIOR AND EMULSION FORMATION OF NOVEL FLUOROETHER AMPHIPHILES IN CARBON-DIOXIDE, Fluid phase equilibria, 128(1-2), 1997, pp. 199-219
The limitations of carbon dioxide as a processing fluid are primarily
attributed to its insolubility of polar compounds. The development of
new CO2-philic amphiphiles could resolve the solubility problem. A new
series of fluoroether amphiphiles have been developed to address the
solubility problem. The development of novel fluoroether amphiphiles h
as been completed for sorbitol ester, sulfates and sulfonates. The pri
mary objective was to design and synthesize materials that have strong
polar hydrophilic heads and highly CO2-philic tails, All of the amphi
philes are soluble in carbon dioxide at moderate pressures and have th
e capability of forming WI, WII and WIII type emulsions in CO2. The de
gree of solubility is heavily influenced by amphiphilic structure incl
uding chain length and branching. Pin examination of pressure effect o
n emulsion behavior shows that the high compressibility of carbon diox
ide enables WI --> WIII --> WII phase transitions which are similar to
those found with increased electrolyte concentrations.