Liquid crystals show unique optical properties due to their anisotropic molecular alignment. Liquid-crystalline (LC) materials are applied to optical information display and storage devices because the modulation of the LC molecular alignment can be induced by external stimuli such as heat, electric fields, and light, leading to changes in the macroscopic optical properties. Of these, light has the advantages of providing stimuli i) to specific chromophores in the molecules by selective-wavelength irradiation, ii) to sub-micrometer-sized areas, and iii) in non-contact with targets. To use light stimuli for the induction of changes in the LC molecular alignment, photochromic reactions are effective.[1±9] The photochromic reactions can reversibly change phases, the director of LC molecules, and the periodicity of molecular alignment. Introduction of photochromic properties to LC composite systems will be useful for the development of the liquid crystals as advanced functional materials. Recently, the combination of liquid crystals and fibrous aggregates of gelators, which are self-assembled by intermolecular interactions such as hydrogen bonding and p±p interactions, has been found to form LC physical gels.[10±19] The LC physical gels show unique optical properties and dynamic functions caused by cooperative effects of liquid crystals and a fibrous network of gelators.[10±21] The LC molecules in the gels respond to external stimuli such as heat and electric fields because of their microphase-separated structures, although they are moderately fixed by the fibrous network of the gelators. If photochromic properties are introduced into these LC physical gels, dynamic change in anisotropic composite structures, which is not available for the physical gels of common organic solvents, can be induced by the light stimuli. Here, we report that photoresponsive LC physical gels exhibit new properties as anisotropic materials: i) the photoinduced structural changes between two different LC gel states;ii) the application of these structural changes to re-writable information recording. These gels were prepared by the addition of trans-(1R,2R)-bis(acylamino)cyclohexane (1) [22] to a room-temperature nematic liquid crystal, 4-cyano-4¢-pentylbiphenyl (2) (Fig. 1). Compound 1 is a newly designed chiral gelator with photochromic azobenzene moieties.When a mixture consisting of the liquid crystal 2 and a small amount of gelator 1 with trans-azobenzene moieties (trans-1) is heated, it becomes an isotropic liquid (isotropic sol state) due to the dissociation of hydrogen bonds (Fig. 2a). Upon subsequent cooling, trans-1 first self-assembles through hydrogen bonds of amide units, leading to the formation of a normal isotropic gel. For example, the sol±gel transition of the mixture containing 3 wt.-% of 1 occurs at 64 C. On further cooling, 2 forms the mesomorphic state in the aggregated network of trans-1 at 34 C inducing the transition to the nematic LC gel at room temperature (Fig. 2b).The photoinduced gel±sol transition of the LC phy...

Nanostructures can be used for the fabrication of highly functional materials transporting ions and charges. We demonstrate a new design strategy for polymeric higher ion-conductors. Phase-segregated layers of alternating mobile tetra(ethylene oxide)s (TEOs) and rigid aromatic cores where the TEO moieties are grafted from aromatic layers have been shown to be efficient to transport lithium triflate. Such segregated structures at the nanometer scale (nano-segregated structures) were prepared by in-situ photopolymerization of an aligned methacrylate liquid crystalline monomer comprising a terphenyl rigid rod mesogen having a TEO terminal chain. The ion-conductive TEO moiety remains in the highly mobile state even after polymerization, which is indicated by its low glass transition temperature (-45 degrees C). This nanostructured film exhibits an ionic conductivity parallel to the layer of 10(-3) S cm(-1) at room temperature. The highest ionic conductivity is in the level of 10(-2) S cm(-1) observed at 150 degrees C. The anisotropic ionic conductivities have been observed for the nano-segregated film.