Alignment Change of Discotic Liquid Crystal Domains with Wavelength Tunable CO2 Laser Irradiation

2010 ◽  
Vol 428-429 ◽  
pp. 284-287
Author(s):  
Hirosato Monobe ◽  
Yo Shimizu
Keyword(s):  
Liquid Crystal ◽  
Laser Irradiation ◽  
Liquid Crystalline ◽  
Device Fabrication ◽  
Vibration Band ◽  
Discotic Liquid Crystal ◽  
Wavelength Tunable ◽  
Crystalline Semiconductor ◽  
Linearly Polarized ◽  
Stretching Vibration

Infrared-induced alignment change with wavelength tunable CO2 laser irradiation for columnar liquid crystal domains was investigated for a triphenylene-based discotic liquid crystal. A uniformly aligned alignment change of domains was observed when a plused linearly polarized infrared laser light corresponding to the wavelength of the aromatic C-O-C stretching vibration band (9.65µm) was irradiated while it was not re-aligned uniformly with continious wave irradiation. The results strongly imply that the infrared irradiation is a possible technique for device fabrication by use of columnar mesophase as a liquid crystalline semiconductor.

Linearly polarized electroluminescence device in which the polarized plane can be rotated electrically using a chiral liquid crystalline semiconductor

2020 ◽  
Vol 4 (7) ◽  
pp. 2137-2148 ◽  
Author(s):  
Masahiro Funahashi ◽  
Yuki Mori
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Crystal Phase ◽  
Liquid Crystal Phase ◽  
Crystalline Semiconductor ◽  
Chiral Liquid Crystal ◽  
Electroluminescence Device ◽  
Linearly Polarized ◽  
Dc Bias

The polarized plane of linearly polarized electroluminescence is rotated by DC bias application during a phase transition of a chiral liquid crystal phase.

Wavelength-tunable linearly polarized luminescence film constructed using a highly efficient luminescent liquid crystal with stimuli-responsive property

2020 ◽  
Vol 8 (46) ◽  
pp. 16561-16568
Author(s):  
Lei Tao ◽  
Kai Lan ◽  
Cheng-Long Zhong ◽  
Ying-Jie Zhou ◽  
Ping Wang ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Stimuli Responsive ◽  
Wavelength Tunable ◽  
Highly Efficient ◽  
Polarized Luminescence ◽  
Linearly Polarized ◽  
Responsive Behavior

A wavelength-tunable linearly polarized luminescense is prepared by in situ photopolymerization of a reactive luminescent monomer with stimuli-responsive behavior.

Synthesis and phase behavior of mesogen-jacketed liquid crystalline polymer with triphenylene discotic liquid crystal mesogen unit in side chains

RSC Advances ◽  
2014 ◽  
Vol 4 (97) ◽  
pp. 54158-54167 ◽  
Author(s):  
Jianfeng Ban ◽  
Sheng Chen ◽  
Hailiang Zhang
Keyword(s):  
Liquid Crystal ◽  
Phase Behavior ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Side Chains ◽  
Discotic Liquid Crystal

Phase behavior of mesogen-jacketed liquid crystalline polymer with triphenylene discotic liquid crystal mesogen unit.

Liquid Crystal Alignment on Photoreactive Side-Chain Liquid-Crystalline Polymer Generated by Linearly Polarized UV Light

1997 ◽  
Vol 30 (21) ◽  
pp. 6680-6682 ◽  
Author(s):  
Nobuhiro Kawatsuki ◽  
Hiroshi Ono ◽  
Hirohumi Takatsuka ◽  
Tohei Yamamoto ◽  
Osamu Sangen
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Uv Light ◽  
Crystalline Polymer ◽  
Side Chain ◽  
Liquid Crystal Alignment ◽  
Linearly Polarized ◽  
Crystal Alignment

scholarly journals Synthesis, Characterization and Computational Study of Discotic Liquid Crystal Compounds

2021 ◽  
Vol 17 (4) ◽  
pp. 63-80
Author(s):  
Hussein Abood Idham ◽  
Hanaa Kaain Salih ◽  
Ibtisam Khalifa Jassim
Keyword(s):  
Liquid Crystal ◽  
Optical Microscopy ◽  
Liquid Crystalline ◽  
Energy Gap ◽  
Computational Study ◽  
Polarized Optical Microscopy ◽  
Molecular Parameters ◽  
Hartree Fock ◽  
Discotic Liquid Crystal

Discotic liquid crystal compounds were synthesized and characterized. Liquid crystalline texture of these compounds was investigated by polarized optical microscopy (POM). The Hartree-Fock approximation (HF) was used to calculate theoretical molecular parameters for synthesized compounds such as optimization, hardness, EHOMO, ELUMO, and energy gap using the Gaussian 09W program.

OPTICAL ANISOTROPY AND FOUR POSSIBLE ORIENTATIONS OF A NEMATIC LIQUID CRYSTAL ON THE SAME FILM OF A PHOTOCHROMIC CHIRAL SMECTIC POLYMER

2000 ◽  
Vol 09 (01) ◽  
pp. 1-10 ◽  
Author(s):  
LEV M. BLINOV ◽  
RICCARDO BARBERI ◽  
MIKHAIL V. KOZLOVSKY ◽  
VLADIMIR V. LAZAREV ◽  
MARIA P. DE SANTO
Keyword(s):  
Liquid Crystal ◽  
Visible Light ◽  
Nematic Liquid Crystal ◽  
Optical Anisotropy ◽  
Liquid Crystalline ◽  
Uv Light ◽  
Glassy State ◽  
Electric Vector ◽  
Exciting Light ◽  
Linearly Polarized

Spin coated films of a chiral comb-like liquid crystalline copolymer containing azobenzene chromophores in its side chains are optically isotropic in their twisted smectic-like glassy state. In contact with a nematic liquid crystal (5CB, E7, MBBA) they provide a degenerate planar orientation. When irradiated by unpolarized UV light, they orient the same nematics homeotropically. Treated with linearly polarized UV light they orient nematics homogeneously with the director along the electric vector of the exciting light. After a combined irradiation first with unpolarized UV light and then with linearly polarized visible light, the films again provide a homogeneous liquid crystal orientation, this time with the director perpendicular to the visible light electric vector. The phenomena observed are related to the light induced optical anisotropy. Two main processes are responsible for the anisotropy (1) a UV light depletion of trans-isomers of the azobenzene chromophores from the chosen direction and (2) a reorientation of the chromophores by polarized visible light.

scholarly journals Triphenylene discotic liquid crystal trimers synthesized by Co2(CO)8-catalyzed terminal alkyne [2 + 2 + 2] cycloaddition

2013 ◽  
Vol 9 ◽  
pp. 2852-2861 ◽  
Author(s):  
Bin Han ◽  
Ping Hu ◽  
Bi-Qin Wang ◽  
Carl Redshaw ◽  
Ke-Qing Zhao
Keyword(s):  
Liquid Crystal ◽  
Benzene Ring ◽  
Liquid Crystalline ◽  
Cycloaddition Reaction ◽  
Terminal Alkyne ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Ether Linkage ◽  
Discotic Liquid Crystal ◽  
Flexible Spacer

The synthesis of star-shaped discotic liquid crystal trimers using Co2(CO)8-catalyzed terminal alkyne [2 + 2 + 2] cycloaddition reaction is reported. The trimers consist of three triphenylene discotic units linked to a central 1,2,4-trisubstituted benzene ring via flexible spacers. The trimers were synthesized in the yields up to 70% by mixing the monomers with 10 mol % of Co2(CO)8 as the catalyst in refluxing 1,4-dioxane. The liquid crystalline properties were investigated by using polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Trimer 4 with an ester connecting group and a longer spacer exhibited a rectangular columnar mesophase, while 5b and 5c possessing an ether linkage and a shorter spacer display a hexagonal columnar mesophase. The connecting functional group and the length of the flexible spacer between the central benzene ring and the triphenylene units have pivotal influence on the mesomorphism.

Oriental behaviour of some homologues of 4-n-pentyl-phenylthio-4′-n-alkoxybenzoate doped with dichroic dye

2008 ◽  
Vol 16 (3) ◽  
Author(s):  
D. Bauman ◽  
A. Zięba ◽  
E. Mykowska
Keyword(s):  
Liquid Crystal ◽  
Order Parameter ◽  
Liquid Crystalline ◽  
Orientational Order ◽  
Polarized Light ◽  
Emission Spectra ◽  
Smectic C ◽  
Fluorescence Measurements ◽  
Dichroic Dye ◽  
Linearly Polarized

AbstractThe long-range orientational order of three members of 4-n-pentylphenylthio-4′-n-alkoxybenzoate $$ (\bar nS5) $$ series doped with a dichroic dye was studied by means of electronic absorption and fluorescence measurements. The order parameters <P2> and <P4> as well as the orientational distribution function were determined on the basis of absorption and emission spectra of linearly polarized light recorded as a function of temperature in the nematic, smectic A, and smectic C phases. An influence of the dye molecular structure on the orientational order of the dye/liquid crystal mixture was observed. Moreover, the dependence of the order parameter values on the length of the alkoxy chain in liquid crystal molecules was found. It was shown that the order parameter <P4>, obtained from fluorescence measurements, can be helpful in recognizing the second-order or weakly first-order transitions between various liquid crystalline phases.

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.

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