Combining ionic liquids and polyethylene glycols to boost the hydrophobic-hydrophilic range of aqueous biphasic systems.

This work reveals, for the first time, that polymer-ionic-liquid-based aqueous biphasic systems (ABS) exhibit a much wider hydrophilic-hydrophobic range than conventional systems reported to date. Three probe dyes were used to demonstrate that either the polymer-rich or the ionic-liquid-rich layer can serve as the most hydrophobic phase. It was found that the phase polarities can be easily tuned by the choice of an appropriate ionic liquid.