Synthesis and Characterization of Terthiophene-Based Rod-Like Liquid Crystals

2012 ◽  
Vol 532-533 ◽  
pp. 61-65
Author(s):  
Xiao Hui Liu ◽  
Zhong Xiao Li ◽  
Song Ya Zhang ◽  
Jia Ling Pu
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Crystal Phase ◽  
Liquid Crystal Phase ◽  
Schiff’S Base ◽  
Thermally Induced ◽  
H Nmr ◽  
Clearing Point ◽  
Temperature Ranges

With 2,2',5',2''-Terthiophene as starting material, two liquid crystalline compounds containing Schiff’s base unit were synthesized in this paper. The structure of the compounds was confirmed by FTIR and 1H NMR. The thermally induced phase transition behaviors were investigated by POM and DSC, and the temperature ranges of liquid crystal phase of the two compounds were compared. Results showed that the symmetric compound exhibited a lower clearing point temperature and broader temperature range of liquid crystal phase.

scholarly journals Preparation of Series Schiff Bases and Studying of their Liquid Crystalline Behavior

2019 ◽  
Vol 1 (1) ◽  
pp. 17-23
Author(s):  
Bari Muhamd Islamallah
Keyword(s):  
Liquid Crystal ◽  
Chemical Structure ◽  
Liquid Crystalline ◽  
Terminal Group ◽  
Crystal Phase ◽  
Liquid Crystal Phase ◽  
Scanning Calorimetry ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Terminal Chain

Our study deals with   preparation   of two types of imine compounds differ in the type of terminal group, where one of them has a terminal carboxyl group COOH while the other contains methoxyOCH3 as a terminal group. In the first part of this research it was Identification by spectroscopy methods using infrared IR and nuclear magnetic resonance H NMR spectrum, besides elemental analysis shows the exact chemical structure of the expected synthesized compounds. In the second part was the study of liquid-crystalline behavior by polarized optical microscopy POM and differential scanning calorimetry DSC that showed a liquid crystal phase in the compounds that has odd number of carbon atoms in the terminal chain compounds in the first series, while the second series compounds showed liquid crystal phase in the   compounds that containing even number of atoms of carbon in the terminal chain. DOI: https://doi.org/10.5281/zenodo.3376373

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

Antiferroelectric Liquid Crystals from Achiral Molecules And A Liquid Conglomerate

1999 ◽  
Vol 559 ◽  
Author(s):  
David M. Walba ◽  
Eva Körblova ◽  
Renfan Shao ◽  
Joseph E. Maclennan ◽  
Darren R. Link ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Crystal Phase ◽  
Liquid Crystal Phase ◽  
Crystalline Structures ◽  
Chiral Liquid Crystal ◽  
Antiferroelectric Liquid Crystals ◽  
Liquid Crystal Structure

ABSTRACTUntil recently, it was an empirical fact that creation of a chiral liquid crystal phase required enantiomerically enriched molecules. In addition, to date known ferroelectric and antiferroelectric smectics have also been composed of enantiomerically enriched molecules. Herein are described the first examples of the formation of chiral and antiferroelectric supermolecular liquid crystalline structures from achiral molecules. In one case (apparently metastable) the liquid crystal structure is macroscopically chiral, with samples composed of heterochiral macroscopic domains: a liquid conglomerate.

scholarly journals Triphenylamine- and triazine-containing hydrogen bonded complexes: liquid crystalline supramolecular semiconductors

2021 ◽  
Author(s):  
Beatriz Feringán ◽  
Roberto Termine ◽  
Attilio Golemme ◽  
Jose M. Granadino-Roldan ◽  
Amparo Navarro ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Charge Transport ◽  
Transport Properties ◽  
Liquid Crystalline ◽  
Crystal Phase ◽  
Liquid Crystal Phase ◽  
Hole Transporting ◽  
Hole Transporting Materials ◽  
Bonded Complexes ◽  
Hydrogen Bonded

Despite the fact that triphenylamine derivatives have been widely explored as hole-transporting materials, studies on charge transport properties in the liquid crystal phase have been overlooked. Here, it is reported...

Interplay Between the Crystal and Liquid Crystalline Ordering of iPP and Carbon Nanotube Composites under Melt-Shear

2011 ◽  
Vol 1308 ◽  
Author(s):  
Georgi Georgiev ◽  
Michael B. McIntyre ◽  
Robert Judith ◽  
Erin A. Gombos ◽  
Peggy Cebe
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Smectic Phase ◽  
Crystal Phase ◽  
Sudden Increase ◽  
Two Dimensional ◽  
Liquid Crystal Phase ◽  
Smectic Liquid Crystal ◽  
Polarized Microscopy ◽  
Nanotube Composites

ABSTRACTCarbon nanotubes (CNTs) exhibit liquid crystalline order and their nematic director couples to the one of low molecular weight liquid crystals. Here we explore the interactions between CNTs and the smectic liquid crystal phase of a polymer and the possibility for a similar coupling in this system. Isotactic Polypropylene (iPP) and iPP/CNTs nanocomposites were made in solution with varying CNT concentrations and hot pressed into 50-100μm thick films. The pure iPP and iPP/CNT films were then sheared at one rotation per second in the melt state. Shearing continued as the temperature was decreased from 200°C to 145°C to induce a smectic liquid crystal phase. The sheared samples were analyzed using polarized optical microscopy, Two Dimensional Microscopic Transmission Ellipsometry (2D-MTE) and Two Dimensional Wide Angle X-Ray Scattering (2D-WAXS). During shearing we detected a sudden increase of birefringence at 151°C in the samples, higher than the iPP crystallization temperature, indicating liquid crystalline ordering. The samples were then crystallized at 135°C for 30 minutes. We measured anisotropic 2D-WAXS patterns of the samples that contained CNTs, indicating strong ordering of the crystals. Upon reheating, we measured birefringence at temperatures higher than the melting endotherm for the iPP crystals, using polarized microscopy, which indicates that some smectic order still persists in the samples, even after crystallization and complete melting of all crystals. Our results indicate that CNTs couple to the smectic phase of iPP, improve its order upon shearing and the crystals created after the formation of the oriented smectic phase are strongly aligned parallel to the direction of shearing.

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.

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