scholarly journals Four Decades of Organic Chemistry of closo-Boranes: A Synthetic Toolbox for Constructing Liquid Crystal Materials. A Review

1999 ◽  
Vol 64 (6) ◽  
pp. 895-926 ◽  
Author(s):  
Piotr Kaszynski
Keyword(s):  
Organic Chemistry ◽  
Liquid Crystal ◽  
Functional Groups ◽  
Liquid Crystalline ◽  
Dipole Moments ◽  
Organic Functional Groups ◽  
Liquid Crystal Materials

Introduction and transformations of organic functional groups to ten- and twelve-vertex closo-boranes and heteroboranes is reviewed in the context of preparation of liquid crystalline compounds. The review, containing 198 references, is designed as a synthetic manual for materials chemists and focuses on methods for engineering molecules with elongated shapes and variable dipole moments. Several underdeveloped aspects of closo-borane chemistry are identified.

scholarly journals Recent progress in luminescent liquid crystal materials: design, properties and application for linearly polarised emission

2015 ◽  
Vol 3 (31) ◽  
pp. 7993-8005 ◽  
Author(s):  
Yafei Wang ◽  
Junwei Shi ◽  
Jianhua Chen ◽  
Weiguo Zhu ◽  
Etienne Baranoff
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Recent Progress ◽  
Materials Design ◽  
Crystalline Materials ◽  
Liquid Crystalline Materials ◽  
Liquid Crystal Materials

Fluorescent and phosphorescent liquid crystalline materials are reviewed with a focus on their application in polarised OLEDs.

Investigations of twist elastic constant K22 of new nematic liquid crystal materials using threshold IPS method

2011 ◽  
Vol 19 (1) ◽  
Author(s):  
J. Parka ◽  
M. Dąbrowski ◽  
R. Kowerdziej
Keyword(s):  
Liquid Crystal ◽  
Elastic Constant ◽  
Nematic Liquid Crystal ◽  
Elastic Constants ◽  
Liquid Crystalline ◽  
Voltage Characteristic ◽  
Crystalline Materials ◽  
Liquid Crystalline Materials ◽  
Better Than ◽  
Liquid Crystal Materials

AbstractThe liquid crystal technology is one of the most popular at the present time. To the most important parameters of liquid crystals belong optical anisotropy, viscosity, and twist elastic constants. One of the most difficult and problematic to measure parameters is a twist elastic constant K22. For new liquid crystalline materials, we have to characterize their physical properties, also a twist elastic constant K22.As a final result of this work, a twist elastic constant of new nematic liquid crystal materials was investigated. In this paper, a transmission-voltage characteristic of the in-plane switching cell was observed to find Freedericksz threshold, and then twist elastic constants could have been calculated. The method was checked on well-characterized materials E7 and 6-CHBT and its accuracy was better than 20%. In addition, the temperature dependence of K22 was determined for all materials.

scholarly journals Design of Tunable Holographic Liquid Crystalline Diffraction Gratings

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6789
Author(s):  
Katarzyna A. Rutkowska ◽  
Anna Kozanecka-Szmigiel
Keyword(s):  
Liquid Crystal ◽  
Communication Networks ◽  
Optical Communication ◽  
Liquid Crystalline ◽  
Incident Light ◽  
Diffraction Gratings ◽  
Lagrange Equations ◽  
Experimental Conditions ◽  
Molecular Distribution ◽  
Polarization Gratings

Tunable diffraction gratings and phase filters are important functional devices in optical communication and sensing systems. Polarization gratings, in particular, capable of redirecting an incident light beam completely into the first diffraction orders may be successfully fabricated in liquid crystalline cells assembled from substrates coated with uniform transparent electrodes and orienting layers that force a specific molecular distribution. In this work, the diffraction properties of liquid crystal (LC) cells characterized by a continually rotating cycloidal director pattern at the cell substrates and in the bulk, are studied theoretically by solving a relevant set of the Euler-Lagrange equations. The electric tunability of the gratings is analyzed by estimating the changes in liquid crystalline molecular distribution and thus in effective birefringence, as a function of external voltage. To the best of our knowledge, such detailed numerical calculations have not been presented so far for liquid crystal polarization gratings showing a cycloidal director pattern. Our theoretical predictions may be easily achieved in experimental conditions when exploiting, for example, photo-orienting material, to induce a permanent LC alignment with high spatial resolution. The proposed design may be for example, used as a tunable passband filter with adjustable bandwidths, thus allowing for potential applications in optical spectroscopy, optical communication networks, remote sensing and beyond.

Characterization of some mesogenic alkyl 1-thioglycosides

2002 ◽  
Vol 80 (8) ◽  
pp. 1162-1165 ◽  
Author(s):  
B Henrissat ◽  
G K Hamer ◽  
M G Taylor ◽  
R H Marchessault
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Solid State ◽  
Solid State Nmr ◽  
Liquid Crystalline ◽  
Liquid Crystal Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Liquid Crystalline Phases

A series of dodecyl 1-thio-β-D-glycosides has been synthesized and characterized (DSC, NMR, CP MAS, X-ray diffraction) as possible new marking materials with liquid-crystalline properties. These compounds undergo solid to liquid crystal phase transitions at various temperatures, which depend on the nature of the carbohydrate part of the structure. Their liquid-crystalline phases show extreme shear thinning behaviour.Key words: liquid crystal, powder X-ray diffraction, phase transition, thioglycoside, solid-state NMR, marking material

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