Hydrogen-bonded liquid crystalline materials: Supramolecular polymeric assembly and the induction of dynamic function

Liquid crystals are molecular materials that combine anisotropy with dynami c nature. Recently, use of hydrogen bonding for the design of functional li quid crystalline materials has been shown to be a versatile approach toward the control of simple molecularly assembled structures and the induction o f dynamic function. A variety of hydrogen-bonded liquid crystals has been p repared by molecular self-assembly processes via hydrogen bond formation. R od-Eke and disk-like low-molecular weight complexes and polymers with side- chain, main-chain, network, and guest-host structures have been built by th e complexation of complimentary and identical hydrogen-bonded molecules. Th ese materials consist. of closed-type hydrogen bondings. Another type of hy drogen-bonded liquid crystals consists of open-type hydrogen bonding. In th is case, the introduction of hydrogen bonding moieties, such as hydroxyl gr oups, Induces microphase segregation leading to liquid crystal-line molecul ar order. Moreover, liquid crystalline physical gels have been prepared by the molecular aggregation of hydrogen-bonded molecules in non-hydrogen-bond ed liquid crystals. They show significant electrooptical properties, An ani sotropic gel is a new type of anisotropic materials forming heterogeneous s tructures.