Effect of ionic liquid on the polarity and size of the reverse micelles in supercritical CO2

The insoluble nature of ionic liquids (ILs) in SC CO2 provides excellent opportunity to study how very small amount of polar solvent affects the properties of reverse micelles in SC CO2. In this work, phase behavior study, UV–vis and small angle X-ray scattering (SAXS) techniques were used to invistigate the effect of IL, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), on the size and micropolarity (in the reverse micelles) of the reverse micelles formed by surfactant Surfynol-2502 (SF) in SC CO2. It is very interesting that the micropolarity and the size of the reverse micelles increase considerably with the increase of the amount of solubilized IL as its amount is extremely small. The results of this work provide some valuable information about how the solubilized polar solvent affect the properties of the reverse micelles as its amount is extremely small.