Nano-Hybrid Liquid Crystals from the Self-Assembly of Surfactant-Encapsulated Polyoxometalate Complexes

The construction of nano-hybrid liquid crystals (LCs) has been intensively pursued because the unique traits of nano-objects together with the self-assembly features of LCs allow the development of novel anisotropic materials. Self-assembly of surfactant-encapsulated polyoxometalate (SEP) complexes, consisting of nano-sized cores and organic shells, provides particularly important contribution in this area. The main motivation for developing those nano-hybrid liquid crystals originates from the added-value combination between anionic polyoxometalates and cationic surfactants. This account describes recent work in our group to develop thermotropic SEP complexes that result from the sophisticated molecular design. Since the polyoxometalates possess well-defined topology, strictly mono-dispersed size, and precise surface charges, it is possible to get more insight into understanding of the influence of nature of components on the thermal property of nano-hybrid LCs. We briefly describe the general importance and advantage of nano-hybrid LCs. We then highlight the synthesis and characterization of thermotropic liquid crystals based on polyoxometalate nano-clusters. The driving forces behind the molecular self-assembly are discussed in depth. The various factors, including chain length, surfactant density and the size-matching effect, affecting the interfacial curvature and the LC properties are summarized. We expect that the structure-property relationships are virtually helpful for the design of new nano-hybrid LC materials.