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Global warming, due to the consumption of fossil energy, is one of the biggest challenges in recent days. Air conditioning (cooling and heating) of office and residential buildings is one of the largest energy consumptions. One way to reduce the energy consumption is to use switchable architectural windows, which can control radiant energy flow. Herein, a smart thermally switchable window with transmittance sensitive to ambient temperature is reported. This smart window is based on a liquid crystal (LC) whose orientation varies with temperature. At temperatures lower than a low threshold temperature, such as in winter, the LC orients perpendicular to the window substrate, and the window is transparent and lets sunlight pass it to warm interiors of buildings. At temperatures higher than a high threshold temperature, such as in summer, the LC orients parallel to the substrate. The window becomes absorbing and blocks sunlight, resulting in a reduction of the solar heating. When temperature varies between these two thresholds, the window has gray‐level transmittances. It does not use electricity and is very energy‐saving, and has an immense potential in applications of smart architectural and vehicle windows.

The molecule of the title compound {systematic name: 17,35-bis[(2-propyn-1-yloxy)methyl]-2,5,8,11,14,20,23,26,29,32-decaoxatricyclo[31.3.1.115,19]octatriaconta-1(37),15,17,19 (38),33,35-hexaene}, C36H48O12, has crystallographic inversion symmetry and adopts a chair-like conformation. The polyether bridges of the macrocycle adopt gauche conformations and the cavity of the macrocycle is collapsed. In the crystal structure, there are weak intermolecular C—H...O hydrogen bonds driven in part by the elevated acidity of acetylenyl H atoms.

The article explains the various mechanisms that are involved in the fast-photon-mode reversible handedness inversion of different self-organized helical superstructures. The two light-driven cyclic azobenzenophanes observed in the study are shown to exhibit extremely high solubility and helical twisting power.

The experimental studies of a nematic liquid crystal with molecules which formed twisted head-to-head H-bonded dimers are reported. The results show that the material in nematic phase in the droplets exhibited nonzero chirality due to spontaneous chiral phase separation.

Liquid crystal (LC) droplets dispersed in isotropic media are of significant interest for scientific community and great importance for industries. The confinement can generate many fascinating LC director configurations and enable important practical applications. With tangential anchoring condition at the droplet surface, theoretically there are several possible configurations: bipolar, twisted bipolar, escaped toroidal, toroidal and so on. Bipolar configuration is usually observed in droplets made from common LCs while the toroidal configuration is rarely observed and it is hard to create especially in thermotropic LCs. Their realisations depend on the splay, bend and twist elastic constants ratio, and anchoring condition of the LC and polymer interface. We constructed thermotropic LCs with abnormally small bend elastic constants, with which stable toroidal configuration were successfully created. We provide a brand new method to create toroidal droplet by simply varying the bend elastic constant. We observed the transition from bipolar configuration to toroidal configuration. We performed a detailed study of the texture of toroidal droplets. [ABSTRACT FROM AUTHOR]

The article focuses on the charateristics and potential applications of limonene as a chiral dopant for liquid crystals. It notes that the chiral molecule D(L)-Limonene is used to induce thermotropic cholesteric-liquid-crystal phase. It mentions that D-Limonene has been substituted for conventional synthesized chiral dopants in a twisted-nematic (TN) cell.

Wide view (WV) film is an important material in the polariser. It is a hybrid-aligned, discotic liquid crystal (DLC) on an alignment layer on the tri-acetyl cellulose film, which is used as compensation film in twisted nematic (TN) mode liquid crystal display (LCD). The relation between the alignment direction of the DLC in the WV film and the rubbing direction of the polyimide on the glass substrate in the TN mode LCD was investigated. The results indicated that the contrast ratio (CR) of the TN mode LCD can be increased by adjusting this angle . When an 88° rubbing angle was used in this work, the CR of the TN mode LCD could reach 1000:1 and the horizontal and vertical viewing angles were 170 and 160°, respectively. [ABSTRACT FROM AUTHOR]

We experimentally studied the nematic-isotropic phase transition of (a) binary mixtures consisting of nematic and racemic liquid crystals and (b) binary mixtures consisting of positive and negative dielectric liquid crystals. We observed that the phase transition temperature is very sensitive to the chemical structures of the constituent components. We also used Maier-Saupe theory to calculate the transition temperature of binary mixtures. By fitting the experimental data, we obtained the interaction coupling constant between the constituent components. [ABSTRACT FROM AUTHOR]

Cholesteric liquid crystals (ChLCs) exhibit two stable states at zero field condition - the reflecting planar state and the nonreflecting focal conic state. ChLCs are an excellent candidate for inexpensive and rugged electronic books and papers. This paper will review the display cell structure, materials and drive schemes for flexible bistable cholesteric (Ch) reflective displays. [ABSTRACT FROM PUBLISHER]

In this paper, we studied the optics of transmissive bistable nematic liquid crystal displays by using the Poincare sphere approach. We derived analytical solutions of the polarization state of the outcoming light for the two bistable states. We have found the optimum modes of film compensated bistable twisted nematic liquid crystal displays. Our results show that the number of optimized modes at a fixed wavelength of film-compensated bistable twisted nematic (BTN) is infinite. We identified the optimized modes for displays operated in the whole visible light wavelength region. We calculated the transmission spectra of the two bistable states of the optimized modes. [ABSTRACT FROM PUBLISHER]

Examines the dual frequency cholesteric light modulators using the cholesteric liquid crystal. Comparison between the transparent and nontransparent state of light shutters; Effects of frequency voltage on transparent homeotropic and reflecting planar textures; Types of liquid crystal light modulators.

Examines the transition among planar, focal conic and homeotropic states of cholesteric liquid crystals by transient dielectric measurement. Creation of a drive scheme to address bistable reflective cholesteric displays; Presence of hysteresis in homeotropic and focal conic transition; Effect of bias voltage on cholesteric transition from field induced state.

Interaction between liquid crystals and alignment layers is of great scientific and technical importance, but is not fully understood. We studied the aligning effect of orthogonally dual rubbed alignment layers in liquid crystal cells. We experimentally observed that with proper numbers of rubbing in the two directions, the generated easy axis of the aligning direction lay between them. We measured the polar and azimuthal anchoring strengths of the alignment layers. We observed that the rubbing in the second direction significantly changed the azimuthal anchoring direction and strength but not the polar anchoring. We theoretically found that Rapini–Papoular formula with quadratic and quartic terms can predict the aligning behavior of the alignment layers. We successfully determined the quartic azimuthal anchoring coefficient. The results are of significance for the understanding of the aligning mechanism of alignment layers. [ABSTRACT FROM AUTHOR]