Photo Alignment and Patterning of Liquid Crystal Polymer Films and Optical Devices by Side-Chain Photopolymers

Prerequisite for virtually all nematic field-effects on which liquid crystal displays (LCDs) are based is stable, uniaxial surface alignment with defined bias tilt angle between the long liquid crystal (LC) axes and their display boundaries. Since the invention of the TN-LCD [1 Schadt, M., & Helfrich, W. (1972). Mol. Cryst. Liq. Cryst., 17, 355.[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]] in 1970 until recently this was achieved by confining liquid crystals between mechanically brushed surfaces [2 Cognard, J. (1982). J. Mol. Cryst. Liq. Cryst. Suppl. Ser., 1, 1–74. [Google Scholar]–4 Aoyama, H., Yamazaki, Y., Matsuura, N., Mada, H., & Kobayashi, S. (1981). Mol. Cryst. Liq. Cryst. Lett., 72, 127.[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]]. We have first shown in the 1990s that, non-mechanical, uniaxial, tilted and patterned LC-alignment is possible by anisotropic Van der Waals surface interactions [5 Schadt, M., Seiberle, H., & Schuster, A. (1996). Nature, 381, 212. US Patent (1995) US-6, 215, 539.[Crossref], [Web of Science ®] , [Google Scholar]], namely by directional polymerization of photo-sensitive side-chain polymers films [5 Schadt, M., Seiberle, H., & Schuster, A. (1996). Nature, 381, 212. US Patent (1995) US-6, 215, 539.[Crossref], [Web of Science ®] , [Google Scholar], 6 Schadt, M., Schmitt, K., Kozinkov, V. & Chigrinov, V.G. (1992). Jpn. J. Appl. Phys., 31, 2155. US patent (1991) US 5,389,698.[Crossref], [Web of Science ®] , [Google Scholar]] by linear polarized UV light. The LPP model is reviewed and its applications enabling high resolution multi-domain liquid crystal displays operated in transmission and reflection are discussed. Examples are given for optical retarders integrated into LCDs, anisotropic liquid crystal polymer (LCP)-films for 3D imaging, interference color filters, wide-view films and anisotropic polymer surface topologies.     

The effect of tourmaline additives in TiO2 photoanode for high-efficiency dye sensitized solar cells

Tourmaline is a kind of borosilicatemineral and has spontaneous polarization property. Due to this property, it can generate a feeble current around 0.06 mA[1 O'Regan, B., &; Grätzel, M. (1991). Nature 353, 737.[Crossref], [Web of Science ®] , [Google Scholar]]. We fabricated the TiO₂ photoanode with different wt.% ratio of tourmaline and investigated the effect of tourmaline additive on dye sensitized solar cells (DSSCs). We carried out electrochemical impedance spectroscopy (EIS) and current density-voltage (J-V) measurement. The results showed that the electron lifetime and the power conversion efficiency of the DSSCs with TiO₂ photoanode containing 3wt% tourmaline were enhanced by about 42% and 20%, respectively, as compared to the DSSCs using pristine TiO₂ photoanode.     

“Synthesis,design and characterization of supramolecular self-assembly of calix[4]resorcinare substituted LCs”

A new class of supramolecular calix[4 (a) Kuang, G.C., Jia, X.R., Teng, M.J., Chen, E.Q., Li, W.S., Ji, Y., Chem Mater. 2012, 24,71–80; (b) Macros, M., Omenat, A., Serrano, J.L., and Ezcurra, A., Adv. Mater. 1992, 4, 285–287.[Crossref], [Web of Science ®] , [Google Scholar], [Google Scholar]]resorcinarene substituted alkoxy side chain (-OC₅H₁₁, -OC₈H₁₇, -OC₁₀H₂₁) has been synthesized and well characterized. These supramolecular compounds were investigated by polarizing optical microscope (POM), differential scanning calorimetry (DSC), thermogravimmetric analysis (TGA) and high-temperature X-ray diffraction studies (XRD). The present synthesized supramolecular derivatives are promising to stabilize the hexagonal columnar phase over a broad thermal range. All the synthesized derivatives showed hexagonal columnar phase at lower temperature and showed enantiotropical nature. Compound 2a with small alkyl spacer on eight side showed higher thermal stability as compare to higher alkyl spacer substituted compounds 2b and compound 2c. These research results suggest that calix[4 (a) Kuang, G.C., Jia, X.R., Teng, M.J., Chen, E.Q., Li, W.S., Ji, Y., Chem Mater. 2012, 24,71–80; (b) Macros, M., Omenat, A., Serrano, J.L., and Ezcurra, A., Adv. Mater. 1992, 4, 285–287.[Crossref], [Web of Science ®] , [Google Scholar], [Google Scholar]]resorcinarene was a good platform to construct bowl-shaped derivatives to exhibits the columnar liquid crystal phase and the observed liquid crystalline properties were greatly effected by the substituted alkoxy side chain on eight side of calix[4 (a) Kuang, G.C., Jia, X.R., Teng, M.J., Chen, E.Q., Li, W.S., Ji, Y., Chem Mater. 2012, 24,71–80; (b) Macros, M., Omenat, A., Serrano, J.L., and Ezcurra, A., Adv. Mater. 1992, 4, 285–287.[Crossref], [Web of Science ®] , [Google Scholar], [Google Scholar]]resorcinarene skeletone. All the synthesized compounds were characterized by FT-IR, ¹H NMR and ¹³C NMR spectroscopy.     

Synthesis and Structure of the Cyclic Borenium Cation 1,1,3,3-tetramethyl-1,3λ<Superscript>4</Superscript>,2-diazaborolidin-1-ium chloride

The solid state structure of an N-heterocyclic borane 1,1,3,3-tetramethyl-1,3λ⁴,2-diazaborolidin-1-ium chloride is reported. This molecule features numerous Cl?H hydrogen bonds.

Graphical Abstract

The crystal structure of 1,1,3,3-tetramethyl-1,3λ⁴,2-diazaborolidin-1-ium chloride shows multiple C–H?Cl interactions in the solid state.

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Synthesis and crystal structure of new phosphate NaFe 4 2+ Fe 3 3+ [PO4]6

New sodium iron orthophosphate NaFe ₄ ²⁺ Fe ₃ ³⁺ [PO₄]₆ was synthesized by the hydrothermal method. The crystal structure (sp. gr. $P\bar 1$ ) was established by the heavy-atom method, with the exact chemical formula of the compound being unknown; R _hkl = 0.0492, R _whkl = 0.0544, S = 0.52. The new compound is analogous to iron phosphate Fe ₃ ²⁺ Fe ₄ ³⁺ [PO₄]₆ studied earlier. However, these two compounds differ in the Fe²⁺ and Fe³⁺ contents, because Na⁺ ions in the new compound are located at the centers of symmetry not occupied earlier.     

Cluster self-organization of TR,Ge-containing crystal-forming systems: Suprapolyhedral precursors and self-assembly of La3Ga[6]Ga 4 [4] Ge[4]O14 (langasite) and La3Ge[6]Ge 2 [5] Ge 2 [4] Ga[4]O16 gallogermanates

A combinatorial-topological analysis of the La₃Ga^[6]Ga ₄ ^[4] Ge^[4]O₁₄ and La₃Ge^[6]Ge ₂ ^[5] Ge ₂ ^[4] Ga^[4]O₁₆ gallogermanates, which have MT and MPT microporous frameworks composed of M octahedra (GeO₆, GaO₆), T tetrahedra (GeO₄, GaO₄), and P pyramids (GeO₅), is performed using the method of coordination sequences with the TOPOS 3.2 program package. It is established that the La₃Ga^[6]Ga ₄ ^[4] Ge^[4]O₁₄ gallogermanate is characterized by a crystal-forming net 6 6 6 (of the graphite type). A new type of the binodal net 6 10 1 0 + 6 10 (2: 1) is revealed in the La₃Ge^[6]Ge ₂ ^[5] Ge ₂ ^[4] Ga^[4]O₁₆ gallogermanate. The cyclic cluster precursors composed of six polyhedra with a lanthanum template atom at the center of the LaMT ₅ and LaMP ₃ T ₃ clusters are identified by the two-color decomposition of the nets in the structures of the La₃Ga^[6]Ga ₄ ^[4] Ge^[4]O₁₄ and La₃Ge^[6]Ge ₂ ^[5] Ge ₂ ^[4] Ga^[4]O₁₆ gallogermanates. The coordination numbers of the cluster precursors in these structures are found to be equal to 6 and 4 for two-dimensional nets and 8 and 6 for three-dimensional nets, respectively.     

Synthesis,Characterization, and Crystal Structure of (2<Emphasis Type="Italic">E</Emphasis>)-3-(4-Fluorophenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one

The title chalcone, of formula C₁₅H₁₁F₁O_2, crystallized in the orthorhombic space group P2₁2₁2₁ (# 19) with crystal parameters a?=?6.9998(8) Å, b?=?12.6740(15) Å, c?=?12.8997(15) Å, V?=?1144.4(2) ų, Z?=?4, determined at 100 K with MoKα radiation. The solid-state structure displays an intramolecular S(6) hydrogen bond and the crystal architecture is maintained by intermolecular F?H, O?H, and C?C short contacts. A DFT geometry optimization is compared with the experimental structure. As ¹⁹F NMR spectroscopy can be used for metabolic tagging of biologically active compounds (including chalcones), the solution-state ¹⁹F chemical shift and ¹³C¹⁹F coupling constants (ⁿJ) are also reported.

Graphical Abstract

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