Ionic Liquid Solvents for the Structuring of Amphiphilic Block Copolymers

In the context of developing self-assembly as a useful approach to the synthesis and manufacturing of complex systems and materials, our group has a long-standing interest on the utilization of selective solvents for the modulation of the organization of amphiphilic molecules such as block copolymers and surfactants. Room-temperature ionic liquids (ILs) have emerged as solvents with unique properties, including low vapor pressure and high thermal stability. We are exploring the self-assembly of block copolymers in ionic liquids, as affected by the ionic liquid chemical composition and intermolecular interactions, and as reflected in the stability, structure and characteristic length-scales of ordered (lyotropic liquid crystalline) phases formed by the amphiphile. We discuss here the structuring of poly(ethylene oxide)-poly(propylene oxide) block copolymers in the ionic liquids ethylammonium nitrate (EAN), 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4), and 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6), and their mixtures with water.