Liquid Crystals

This article discusses modern directions of research in liquid crystals (LCs). LCs represent one of the best studied classes of soft matter, along with colloids, polymer solutions and melts, gels, and foams. Phenomena observed in LCs and approaches developed for their description become of heuristic value in other branches of science. This article considers the basic properties of low-molecular weight thermotropic LCs, with an additional emphasis on the developments of the last decade, such as LC colloids. It begins with an overview of thermotropic and lyotropic systems, followed by a review of the concept of order parameter, elasticity, surface anchoring, and topological defects. It also evaluates hybrid systems combining LCs with polymers or colloids, along with new ways of creating mesomorphic systems and the dynamics of LCs, including anisotropic viscosity, director dynamics and the Frederiks transition, and flow induced by thermal expansion. Finally, it describes various applications of LCs.