Chapter 3: CO₂-switchable Aqueous Solutions

The properties of aqueous mixtures are functions of both the properties of water itself, and the properties of the materials dissolved or suspended in the water. While water isn't CO₂-switchable, aqueous mixtures can be if one or more of the materials in the water are switchable. In this chapter, CO₂-switchable aqueous solutions are described, as well as their application to water cleanup, water removal, and various other tasks. CO₂ as a trigger has been shown to reversibly control aqueous solution density, viscosity, solubilizing power, conductivity, osmotic pressure, and ionic strength, but curiously not the solvatochromic polarity, acidity, or basicity. While the flexibility of these switchable aqueous solutions is impressive, it is still too early to definitively state that they are greener than other alternatives for any specific application.