Reversible solution in the mix

Philip Jessop and colleagues at Queen's University in Kingston Ontario have created a new surfactant that allows oil and water to be mixed and de-mixed on demand. The compound, a long-chain alkyl amidine, could help mitigate the kind of oil spills that are currently threatening the coasts of Lebanon and Syria as well as offering new opportunities for oil extraction from otherwise intractable sources. Carbon dioxide and air are the on and off switches for the new reversible surfactant. Bubble carbon dioxide through a solution and the surfactant switches on, forming an oil-water emulsion. Bubble air through this emulsion and the oil and water separate again, explains Jessop. The researchers explain that ongoing research will help them improve the speed of switching and to optimize their surfactants for particular applications.