Zwitterions as building blocks for functional liquid crystals and block copolymers

Zwitterions are a class of organic salts whose cation and anion are covalently tethered. This characteristic imparts unique physicochemical properties that differ from those of conventional organic salts. Recently, there has been increasing attention paid to the use of these zwitterions as building blocks for functional organic materials due to their unique properties. These materials have been applied to polymers, liquid crystals, dendrimers and nanoparticles. In this review, I focus on the development of nanostructured ionic materials through the organization of zwitterions. The strategies for such development can be roughly classified into two groups: the introduction of liquid-crystalline properties into zwitterions and the design of block copolymers with zwitterionic segments. These zwitterion derivatives show various organizational behaviors, such as self-organization, co-organization with acids or lithium salts and solvent-induced organizational behavior; they also function as unique ionic matrices. The potential applications of these ionic matrices are described.