Self-Assembled Gels formed in Deep Eutectic Solvents - Supramolecular Eutectogels with High Ionic Conductivities.

This paper reports the ability of 1,3:2,4-dibenzylidene-D- sorbitol (DBS), a simple, commercially-relevant compound, to self-assemble as a result of intermolecular non-covalent interactions into supramolecular gels in deep eutectic solvents (DESs). The DESs are based on choline chloride combined with alcohols/ureas - DBS forms gels at a loading of 5% wt/vol. Rheology confirms the gel-like nature of the materials, electron microscopy indicates underpinning nanofibrillar DBS networks and differential scanning calorimetry shows the deep eutectic solvent nature of the liquid-like phase is retained. The ionic conductivities of the gels are similar to those of the unmodified DESs proving the deep eutectic nature of the ionic liquid-like phase. Gelation is tolerant of ionic additives Li+, Mg2+ and Ca2+, with the resulting gels having similar conductivities to electrolyte dissolved in the native DES. The low-molecular-weight gelator DBS is a low-cost additive - forming gels in DESs from readily-available constituents, with conductivity levels suitable for practical applications. We suggest supramolecular eutectogels have potential uses ranging from energy technology to synthesis and catalysis.