Emerging Ionic Soft Materials Based on Deep Eutectic Solvents

In the last 5 years, the use of deep eutectic solvents (DESs) have been opening new perspectives toward the creation of novel ionic soft materials as alternatives to expensive ionic liquids. This Mini-Review Article highlights the progress and advances in soft ionic materials or gels, mostly composed by a DES immobilized within difference matrices, such as linear polymers, polymer networks, biopolymers, supramolecular compounds, or sol-gel derived silica networks. By taking advantage of the DESs characteristics and properties in the solid state, this building system delivers a variety of tailor-made materials showing different functionalities (ionic conductivity, self-healing, stretchability and pH-responsiveness) and offers a way to circumvent drawbacks related to shaping and risk of leakage in many technological applications. In this context, we provide a judicious analysis of these emerging ionic soft materials, their properties, and applications open in energy, (bio)electronics, drug delivery, analytical chemistry, and wastewater treatment. Perspectives and opportunities for future research directions on this blossoming field are also discussed.