Jianling Zhang and co-workers, Chinese Academy of Sciences, have created a CO₂-in-ionic liquid (IL) microemulsion. An IL/surfactant mixture was saturated with increasing amounts of CO₂. At low CO₂ pressures, the surfactant formed dry micelles dispersed in the IL (see picture, a). As the pressure exceeded the saturated vapor pressure of CO₂, liquefied CO₂ entered into the micellar cores to form CO₂ domains. This led to first CO₂-bound micelles (b), and then CO₂-swollen micelles (c).

The CO₂-swollen micelles are tunable as the micellar size can be easily adjusted by the pressure of CO₂. The continuous phase — the ionic liquid — also has the potential to be adjusted due to the tunable and designable nature of ILs that aries from the multiple anion and cation combinations that are possible.

This novel kind of microemulsion has potential applications in various fields, such as materials synthesis, chemical reactions, and extraction.

^{Images: © Wiley-VCH}

• Carbon Dioxide in Ionic Liquid Microemulsions
  J. Zhang, B. Han, J. Li, Y. Zhao, G. Yang,
  Angew. Chem. Int. Ed. 2011.
  DOI: 10.1002/anie.201103956