Spontaneously formed nano-sized emulsions
Oeiras, 14.03.2014
Nanoscale emulsions promise a wide range of applications. They can solubilise a variety of polar and nonpolar substances in their nanodomains; therefore, they are useful as microreactors or drug delivery systems, are employed in the purification and extraction of biomolecules, and can serve as templates in the synthesis of nanostructures. Their main disadvantage is that these liquid/liquid dispersions normally require high concentrations of surfactant. Researchers from the Lab of Molecular Thermodynamics have shown that ionic liquids (ILs) can spontaneously form nano-sized IL-in-water emulsions in a basically two-component system consisting of an aqueous solution of inorganic salt and a water-immiscible ionic liquid. This work is published in Soft Matter journal (IF = 3.9).
The ionic liquid ions play a dual role, that of both surfactant and dispersed phase. No extra surfactant is needed to promote emulsification. Such behaviour highlights the unique versatility of the ionic liquids – here the individual compartments of the ionic liquids have the characteristics of an oil (in their initial configuration) or of a surface active component (when combined with the aqueous inorganic ions). Moreover the process is spontaneous - simply put toghether the two liquids and tiny ionic liquids droplets are generated in water. No energy input is required. This aspect of emulsification is both, a still under debate scientific phenomenon and potentially significant factor from the perspective of industrial applications.
Researchers have demonstrated some ways of applying the IL-in-water emulsions. They were employed to template the formation of nanoparticulate and porous films as well as loadable microcrystals that could be used as carrier and delivery systems.
Original Article
Soft Matter (2014) DOI: 10.1039/C4SM00213J
Spontaneous emulsification in ionic liquid/water systems and its use for solids templating
Magdalena Kowacz, José M.S.S. Esperança and Luís Paulo N. Rebelo
