Smart separations with ionic liquids

Room temperature ionic liquids are an interesting class of materials as these have a solubility gap with most of the liquids we commonly use, such or organic solvents.

Ionic liquids are composed of equal number of positively and negatively charged ions. Both ions are ‘encapsulated’ by some organic moieties so that the charges cannot come in direct contact. Electrostatic correlation forces dictate that the ions should be in each other’s proximity. The hydrophobic coats prevent the solvation with water and bulky hydrophobic molecules cannot swell the IL either.

We like to use ionic liquids for separation purposes, e.g. to separate lipids from proteins in such a way that the proteins remain intact (i.e. retain structural integrity). We therefore formulate the ILs in water so that there is a large surface area between the IL and water. This calls for the making of IL-in-water emulsions. In this project we search for strategies to make such an emulsion. We use our experience in the field of complex coacervates to formulate the systems.

We are interested in fundamental aspects of the ionic liquid-water interface and how effective emulsifiers can reduce the IL-water interfacial tension. To understand such questions we need to understand the forces that keep the IL phase together, that is, we search for the role of electrostatics and evaluate how strong these are in comparison to, e.g., hydrophobic forces.

Anticipating polymeric emulsifiers we are planning to use thermo-responsive polymers to control the colloidal stability of the IL-in-water emulsions. Smart separation applications further are anticipated by the use of magnetic responsive ILs. Such emulsions can be separated by an external magnetic field.