We synthesized small-angle bent-core liquid-crystalline (LC) molecules based on a 1,2-bis(phenylethylene) benzene central core, containing seven aromatic rings and alkoxy tails with carbon numbers of 12, 16 and 18. This ortho-bistolane central core offers a 60° bend angle. Irrespective of this unusually small angle, these molecules can form banana smectic phases with a ferroelectric B7-antiferroelectric B2 phase sequence upon cooling as clarified from the micoscopic, X-ray and opto-electric observations. This indicates that despite of the low bend angle of 60°, these are able to be still packed into a layer with the polar bent direction parallel to the layer like ordinal banana molecules. The present result is striking since it had been believed that banana phases can only be stabilized when the bending angle is in the range from 110-140°, providing additional insight into the nature of banana-shaped molecules.
Japan Science and Technology Agency (JST) have launched a new program called strategic promotion of innovative
research and development ( S-Innovation ). Projects chosen for the S-Innovation program are selected from among the
research output of JST's strategic and basic research programs, such as CREST, ERATO, Sakigake and PREST, which
aim to create innovative new technologies, lead to the advancement of science and technology and the emergence of new
industries. S-Innovation covers R&D themes from the aforementioned programs and is based on the seamless, long-term
pursuit of R&D toward the practical application of novel technologies. It is envisaged that the innovation resulting from
such technologies will form the foundations of future industries. Currently the program consists of four projects in which
photonics polymers are included. The photonic polymer research consists of five topics such as development of fast
organic photorefractive polymers for advanced optical communication technology, development of new device
technology based on nano-ordered structures of polymers, development of three-dimensional vector wave memory,
optical interconnect device technology using high performance photonic polymers and development of quantum
photonic technologies with polymer optical nano-fibers. Each topic is funded approximately $1.0 M/year for ten years.
The objectives and unique features of S-innovation and the highlights of each topic are described.
We have studied the lasing characteristics from a dye-doped nematic layer sandwiched by two polymeric cholesteric liquid crystal (PCLC) films as photonic band gap materials. The nematic layer possessing birefringence brings about the following remarkable optical characteristics; (1) reflectance in the photonic band gap (PBG) region exceeds 50% due to the retardation effect, being unpredictable from a single CLC film, (2) efficient lasing occurs either at the notch of PBG or at the photonic band edge, (3) the lasing emisions contain both right- and left-circular polarizations, and (4) tunable lasing can be achieved by the reorientation of nematic liquid crystal molecule under the application of an electric field.
We describe a distinct polar nematic liquid crystal formed from the polar rod-like aromatic polyester which comprises 4-hydroxybenzoaic acid (HBA) and 6-hydroxy-2naphthoic acid (HNA) in a molar ratio of 73/27. The nemtic liquid crystal is biaxial and the polarity appears along both axes as determined by measurements of the second harmonic generation. The polar structure disappeasrs when the molecular weight in polyester is decreased, showing that the large dipole moment of each chain is responsible for the polar ordering. The strong dipole-dipole interaction between polar rod-like molecules may be ascribed to the origin of the polarility.
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