Functional Design of Ionic Liquids: Unprecedented Liquids that Contribute to Energy Technology, Bioscience, and Materials Sciences

There are increasing numbers of studies on the design and evaluation of functional ionic liquids (ILs). Recent progress of functional ILs has been reviewed here. Applications of ILs as solvents for hardly-soluble materials in ordinary solvents are discussed mainly from the viewpoint of energy conversion. We focus on a potential application of ILs as electrolyte solution substituents not only for battery but also other electrochemical devices. Also, the uses of ILs as solvents for biomolecules, especially for dissolution of proteins are summarized. Recent progress with zwitterionic ILs and polymerized ILs are also reviewed as unique morphology ILs. Mixtures of molecular liquids and ILs are quite interesting systems, and thermotropic phase change of these mixtures is described including some applications.