Masaya Moriyama

Self‐assembly of liquid crystalline triphenylene–oligo(ethylene oxide)–triphenylene molecules and their complexes with lithium triflate

Mesomorphic dimeric molecules consisting of discotic triphenylene rigid units and flexible ethylene oxide spacers have been prepared. The liquid crystalline behaviour is greatly dependent on the length of the ethylene oxide chains. The miscibility and phase behaviour have been examined for mixtures of the materials with lithium triflate.

Photostimulated structural changes of liquid crystal physical gels

Photoresponsive liquid crystal physical gels are formed from a hydrogen-bonded gelator containing photochromic azobenzene moieties and nematic or discotic liquid crystals. The bistable gel structures based on the trans-azobenzene gelator could be achieved by combining the trans-cis photoisomerization of the azobenzene moieties and thermal treat-ment. Upon UV irradiation, the trans-cis photoisomerization causes the transition from the initial gel states to the liquid crystal sol states. The cis-trans back-isomerization causes reaggregation of the trans-gelator in the liquid crystals. This leads to the formation of the second gel states which have the structures reflecting the liquid crystal order. The initial gel states can be reversibly changed to the reformed gel states by photoirradiation and thermal treatments. The photo-induced reversible structural changes of the anisotropic physical gels are applied to rewritable information recordings.

Alignment Properties of Hydrogen-Bonded Mesogens of Supramolecular Liquid-Crystalline Network Films Coated on an Alignment Layer

The films of a supramolecular liquid-crystalline (LC) network were spontaneously formed by intermolecular hydrogen bonds between multifunctional H-bond donor (HD) and H-bond acceptor (HA) molecules. A tricarboxylic acid, 2,5-bis{2-[2-(4-carboxyphenoxy)ethoxy]ethoxy}benzoic acid (1) was prepared for the use as a trifunctional H-bond donor. This donor was complexed with a bifunctional H-bond acceptor, trans-1,2-bis(4-pyridyl)ethylene (2). H-bonded complexes, 1/2, in the various ratio of donor to acceptor groups (HD/HA) were coated on a rubbed poly(vinyl alcohol) (PVA) film. These films exhibited homogeneous alignment when the ratio of HD to HA (HD/HA) was more than 1.025. These results suggest that the alignment properties of the mesogens in the complex films on the PVA film related to the value of HD/HA.