Temperature dependence of the pitch in chiral lyotropic chromonic liquid crystals

Soft Matter ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 109-115 ◽  
Author(s):  
Timothy Ogolla ◽  
Robert S. Paley ◽  
Peter J. Collings
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Temperature Dependence ◽  
Optical Microscopy ◽  
Helical Axis ◽  
Coexistence Region ◽  
Polarized Optical Microscopy ◽  
Chiral Nematic ◽  
Microscopy Image ◽  
Optical Microscopy Image

Polarized optical microscopy image of a fingerprint texture for a lyotropic chromonic liquid crystal entering the chiral nematic–isotropic coexistence region. The helical axis is in the plane of the image and the perpendicular distance between the stripes is around 50 μm, half the chiral nematic pitch.

Synthesis and Mesomorphic Properties of a Series of Cholesteric Liquid Crystals

2010 ◽  
Vol 663-665 ◽  
pp. 759-762 ◽  
Author(s):  
Qing Lan Ma ◽  
Yuan Ming Huang
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Optical Microscopy ◽  
Scanning Calorimetry ◽  
Polarized Optical Microscopy ◽  
Phase Transition Temperatures ◽  
Second Category ◽  
Mesomorphic Properties

A series of cholesterol liquid crystal compounds was synthesized. Phase-transition temperatures and mesomorphic textures of these synthesized compounds were characterized with differential scanning calorimetry and polarized optical microscopy, respectively. In these molecules the terminal ester chains CnH2n-1COO-, where n was the number of carbon atoms in the terminal ester chains, were linked to the cholesterol core. All of the synthesized cholesterol compounds exhibited mesophases for the first heating. However, as temperature decreased from their clearing points, their micrographs can also be divided into two categories, the first category exhibits branch-like mesophase textures for n in the range of 1-10 while the second category exhibits branch-like crystal textures for n in the range of 11-18.

scholarly journals Tuning the photonic properties of chiral nematic mesoporous organosilica with hydrogen-bonded liquid-crystalline assemblies

2015 ◽  
Vol 3 (7) ◽  
pp. 1537-1545 ◽  
Author(s):  
Michael Giese ◽  
Tim Krappitz ◽  
Ronald Y. Dong ◽  
Carl A. Michal ◽  
Wadood Y. Hamad ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Optical Microscopy ◽  
Liquid Crystalline ◽  
Cd Spectroscopy ◽  
Polarized Optical Microscopy ◽  
Mesoporous Organosilica ◽  
Chiral Nematic ◽  
Hydrogen Bonded

The thermochromic behaviour of chiral nematic mesoporous organosilica hybrids infiltrated with hydrogen-bonded liquid crystals was investigated by polarized optical microscopy, UV-vis and CD-spectroscopy.

Synthesis and Application of the Three-Component Lyotropic Liquid Crystal

2015 ◽  
Vol 1095 ◽  
pp. 371-376
Author(s):  
Qiu Li Yang ◽  
Xin Ran Guan ◽  
Xiao Na Xie ◽  
Shao Wei Wei ◽  
Yi Wen Fang
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Ternary System ◽  
Optical Microscopy ◽  
Lyotropic Liquid Crystals ◽  
Lyotropic Liquid Crystal ◽  
Polarized Optical Microscopy ◽  
Texture Structure

This paper focused on synthesizing the surfactant lyotropic liquid crystals (LLCs) through mixing the coconut diethanol amide (6501), primary alcobol ethoxylate (AEO9) and water. The LLCs phases formed in the ternary system are thoroughly investigated by polarized optical microscopy (POM). The obtained LLCs were characterized by XRD and SEM in order to analysis the texture, structure and the transformation. In addition, the LLCs have been applied in the preparation of TiO2nanoparticles in our research. The obtained TiO2powder were characterized by XRD and SEM, more importantly, the results showed that the LLCs are effective in the process of synthesizing TiO2nanoparticles.

scholarly journals New cholesteryl containing bent core liquid crystals

2013 ◽  
Vol 78 (5) ◽  
pp. 669-680 ◽  
Author(s):  
Cosmin-Constantin Huzum ◽  
Irina Carlescu ◽  
Gabriela Lisa ◽  
Dan Scutaru
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Optical Microscopy ◽  
Liquid Crystalline ◽  
Benzoic Acids ◽  
Scanning Calorimetry ◽  
Polarized Optical Microscopy ◽  
Acyl Chlorides ◽  
Esterification Reactions

The paper presents the synthesis and mesomorphic behavior of two new series of bent core liquid crystalline compounds based on a 1,3-dihydroxybezene core and containing a cholesteryl 6-oxyhexanoate wing. The two series were obtained by the esterification of the cholesteryl 6-(3-hydroxyphenoxy)hexanoate core with some 4-((4-(n-alkyloxy)phenyl)azo)benzoic acids (n-alkyl = n-hexyl ? n-dodecyl) or 4-(4-(n-alkyloxy)benzoyloxy)benzoic acids (n-alkyl = n-hexyl ? n-decyl). The esterification reactions were performed via the corresponding acyl chlorides or with the DCC / DMAP system. All the synthesized compounds evidenced enantiotropic liquid crystalline properties, with smectic type textures, when investigated by means of differential scanning calorimetry and polarized optical microscopy. Isotropisation and isotropic to liquid crystal transitions were relatively low (between 89 ? 1460C). The compounds containing the azo-aromatic linking group presented the largest range of stability of the mesophases (between 42 and 870C). All the investigated compounds were thermally stable in the existence range of the mesophases.

A chiral–racemic lyotropic chromonic liquid crystal system

Soft Matter ◽  
2021 ◽  
Author(s):  
Jordan K. Ando ◽  
Peter J. Collings
Keyword(s):  
Liquid Crystal ◽  
Optical Microscopy ◽  
Orientational Order ◽  
Molecular Assemblies ◽  
Polarized Optical Microscopy ◽  
Crystal System ◽  
System P ◽  
Liquid Crystal System

A lyotropic chromonic liquid crystal consists of oriented molecular assemblies in solution. If the molecules are chiral, the helical pattern of orientational order is revealed by the stripes seen with polarized optical microscopy.

Effect of Photo-Isomerization of Azo Dyes on the Photonic Bandgap in Chiral Nematics

2011 ◽  
Vol 181-182 ◽  
pp. 257-260
Author(s):  
David Statman ◽  
Andrew Jockers ◽  
Daniel Brennan
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Azo Dyes ◽  
Azo Dye ◽  
Photonic Bandgap ◽  
Methyl Red ◽  
Central Wavelength ◽  
Chiral Nematic ◽  
Anchoring Energy ◽  
Pitch Length

Chiral nematic liquid crystals prepared with Grandjean texture demonstrate a photonic bandgap whose central wavelength is proportional to the pitch length, P, of the liquid crystal and whose width is given by (ne – no)P. We show that methyl red doped chiral nematics undergo a shift in the photonic bandgap upon photo-isomerization. This shift is a result of (1) photo-induced change in anchoring energy on the nematic surface, and (2) change in the natural pitch length from the photo-isomerization of the azo dye.

Dependence of Phase Transition of a Bent-Core Liquid Crystal on the Heating Rate

2010 ◽  
Vol 663-665 ◽  
pp. 787-790 ◽  
Author(s):  
Qing Lan Ma ◽  
Yuan Ming Huang
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Optical Microscopy ◽  
Heating Rate ◽  
Broad Peak ◽  
Crystal Phase ◽  
Scanning Calorimetry ◽  
Polarized Optical Microscopy ◽  
Crystal Compound

A bent-core liquid crystal compound N,N-bis (4-propoxybenzylidene)benzene- 1,3-diamine was synthesized. Phase transition properties of the synthesized compound with the deferent heating rate were characterized with differential scanning calorimetry and polarized optical microscopy. , respectively. Our results demonstrated that the bent-core compound exhibited the completely undivided multi-phases in heating-rate ranges from 1oC/min to 6oC/min while it showed a broad-peak crystal phase in higher heating-rate ranges of 7-10oC/min for the first heating.

scholarly journals Pressure-induced ionic liquid crystal in 1-dodecyl-3-methylimidazolium tetrafluoroborate

RSC Advances ◽  
2017 ◽  
Vol 7 (42) ◽  
pp. 26428-26433 ◽  
Author(s):  
Xiang Zhu ◽  
Haining Li ◽  
Zheng Wang ◽  
Chaosheng Yuan ◽  
Pinwen Zhu ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Ionic Liquid ◽  
Liquid Crystal ◽  
Optical Microscopy ◽  
Polarized Optical Microscopy ◽  
Phase Behaviors

The phase behaviors of 1-dodecyl-3-methylimidazolium tetrafluoroborate ([C12MIM][BF4]) had been investigated by means of Raman spectroscopy and polarized optical microscopy under pressure values up to 2.0 GPa at the temperature of 80.0 °C.

Laser Diffractions in Lyotropic Liquid Crystal Formed by Liquid Dishiwash

2010 ◽  
Vol 663-665 ◽  
pp. 779-782
Author(s):  
Yuan Ming Huang ◽  
Wei Wei Liu
Keyword(s):  
Liquid Crystal ◽  
Optical Microscopy ◽  
Red Light ◽  
Lamellar Phase ◽  
Lyotropic Liquid Crystal ◽  
Isotropic Phase ◽  
Polarized Optical Microscopy ◽  
Neon Laser ◽  
Helium Neon Laser ◽  
Helium Neon

We demonstrated that a lamellar phase of lyotropic liquid crystal formed by liquid dishwash could assemble themselves into crystal droplets when their isotropic phase was slowly changed into lamellar phase on the glass substrate. Characterization by means of polarized optical microscopy showed that a pattern of liquid crystal droplets was developed in the thin films formed by liquid dishwash. Our laser light diffraction experiments confirmed that these liquid crystal droplets could effectively diffract the incident red light from a helium-neon laser. On the basis of the Fraunhofer diffraction equation, we derived for the diameter of liquid crystal droplets. The diameter of liquid crystal droplet is 42.517 m, and almost agreement with the graph of polarized optical microscopy.

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