Amphiphilic oligoether-based ionic liquids as functional materials for thermoresponsive ion gels with tunable properties via aqueous gelation

Abstract

The aqueous gelation of an amphiphilic ammonium oligoether-based ionic liquid (AMMOENG 102) is addressed and compared to the gelation of a similar compound (AMMOENG 100) recently reported (J. Casamada Ribot, C. Guerrero-Sanchez, R. Hoogenboom and U. S. Schubert, J. Mater. Chem., 2010, 20, 8279.).¹ The comparison is based on proton nuclear magnetic resonance spectroscopy, rheological, ionic conductivity, water uptake, differential scanning calorimetry, surface tension and small angle X-ray scattering investigations. The results demonstrate that slight changes in the chemical structure of these ionic liquids can have an important effect on the properties of their corresponding ion gels. Hence, this contribution provides an insight into the stability and formation mechanism of these new ion gels solely consisting of ionic liquid and water and expands the range of amphiphilic ionic liquids which can be utilized for the straightforward and inexpensive preparation of thermoresponsive materials with tunable properties (i.e., ionic conductivity and melting point) and high mechanical moduli.