Thermoreversible ionogels with tunable properties via aqueous gelation of an amphiphilic quaternary ammonium oligoether-based ionic liquid

Abstract

The gelation of the amphiphilic quaternary ammonium oligoether-based ionic liquid (AMMOENG100) with water is addressed. This approach allows the preparation of thermoreversible ionogels with high ionic conductivity (up to 60 mS cm⁻¹), remarkable mechanical properties (storage moduli above 10⁵ Pa—a value comparable to the mechanical properties of some rubbers), and melting points in the range from −20 to 53 °C. These properties can be easily tuned in a broad range by varying the water (and/or inorganic salts) concentration in the ionogels. The described method is a very convenient way to prepare ionogels because it is based on simple and inexpensive materials, namely AMMOENG100 and water (no volatile organic solvents involved). Infrared measurements suggested that the observed gelation phenomenon might occur via the formation of a hydrogen bonded network between water and the AMMOENG100 ionic liquid.