scholarly journals Synthesis and Characterization of Nonsymmetric Liquid Crystal Dimer Containing Biphenyl and Azobenzene Moiety

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
S. Sandy Subala ◽  
B. Syama Sundar ◽  
S. Sreehari Sastry
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Optical Microscope ◽  
Synthesis And Characterization ◽  
Spectroscopic Methods ◽  
Liquid Crystal Phase ◽  
Smectic A ◽  
Smectic C ◽  
Azobenzene Moiety

Calamitic liquid crystalline dimer containing azobenzene moiety and a decyloxy biphenyl linked by flexible spacers {4-[7-(4′-decyloxy-biphenyl-4-yloxy)-alkyloxy]-phenyl}-(4-decyl-phenyl)-diazene has been synthesized and characterized by spectroscopic methods. The transition temperatures and phase behaviours were studied by Differential Scanning Calorimeter (DSC) and Polarizing Optical Microscope (POM). The synthesized compounds exhibited enantiotropic liquid crystal phase with higher spacer display nematic and smectic C phases while lower spacer shows nematic and smectic A phases.

Synthesis and Characterization of Schiff’s Base Compounds with Octadecylaniline as End Group

2011 ◽  
Vol 181-182 ◽  
pp. 143-146
Author(s):  
M.V.V. Nagi Reddy ◽  
P.V. Datta Prasad ◽  
K. Fakruddin ◽  
R. Jeevan Kumar ◽  
D. Madhavi Latha ◽  
...  
Keyword(s):  
Differential Scanning Calorimeter ◽  
Liquid Crystalline ◽  
Synthesis And Characterization ◽  
Schiff’S Base ◽  
Smectic A ◽  
Smectic C ◽  
First Time ◽  
Phase Variants ◽  
End Group

The liquid crystalline compounds viz, N-(p-n-decyloxybenzylidene)-p-n-octadecyl aniline, 10O.18, N-(p-n-octadecyloxybenzylidene)-p-n-octadecylaniline, 18O.18, (p-n-biphenylbenzylidene) -p-n-octadecylaniline, PB18A and terephthalyidene-bis-p-n-octadecylaniline, TB18A have been synthesized for the first time and the characterization is carried out using thermal microscopy (TM) attached with a hot stage and differential scanning calorimeter (DSC). All the four compounds exhibit a variety of phase variants such as isotropic to smectic-F (Iso-SmF) in 10O.18, isotropic to smectic-F (Iso-SmF) in 18O.18, isotropic to smectic-A to smectic-B (SmA-SmB) in PB18A and isotropic to smectic-C to smectic-I to smectic-F (Iso-SmC-SmI-SmF) in TB18A.

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

Synthesis and characterization of chiral smectic C liquid crystalline terpolysiloxanes

1996 ◽  
Vol 20 (6) ◽  
pp. 681-689 ◽  
Author(s):  
Andy J. Walz ◽  
Ibrahim G. Shenouda ◽  
L.-C. Chien
Keyword(s):  
Liquid Crystalline ◽  
Synthesis And Characterization ◽  
Smectic C

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.

Side Chain Liquid Crystalline Block Copolymers With Chiral Smectic C* Mesogens

1996 ◽  
Vol 425 ◽  
Author(s):  
Wen Yue Zheng ◽  
Paula T. Hammond
Keyword(s):  
Glass Transition ◽  
Block Copolymers ◽  
Anionic Polymerization ◽  
Liquid Crystalline ◽  
Diblock Copolymers ◽  
Side Chain ◽  
Synthesis And Characterization ◽  
Glass Transition Temperatures ◽  
Smectic C

AbstractA new series of side chain liquid crystalline-amorphous diblock copolymers has been successfully synthesized using chiral mesogens. Anionic polymerization techniques have been used to make these monodisperse diblock materials. Preliminary studies suggest that these microphase segregated diblock copolymers exhibit a smectic C* phase. This mesophase exists between and above the glass transition temperatures of the two polymer blocks. Synthesis and characterization of these novel materials are discussed.

SYNTHESIS AND CHARACTERIZATION OF A RODLIKE LIQUID CRYSTALLINE POLYURETHANE OLIGOMER

2010 ◽  
Vol 03 (03) ◽  
pp. 169-172
Author(s):  
CHUN WEI ◽  
QIU-SHAN GAO ◽  
YONG-YANG GONG ◽  
XUE-MEI XIONG ◽  
XIN SHEN
Keyword(s):  
Weight Loss ◽  
Liquid Crystalline ◽  
Room Temperature ◽  
Decomposition Temperature ◽  
Synthesis And Characterization ◽  
Smectic A ◽  
Smectic A Phase ◽  
Ft Ir ◽  
Dimethylformamide Solution

A novel rodlike liquid crystalline polyurethane (LCPU) oligomer was synthesized by polyaddition of hexane-1,6-diylbis(4-hydroxybenzoate) with toluene 2,4-diissocyanate in N, N′-dimethylformamide solution. The properties of the LCPU oligomer were investigated by FT-IR, DSC, TGA, POM, WAXD and SEM. The LCPU oligomer was a yellow powder at room temperature, which maintained a stable rodlike microstructure below its melting point, and had high crystallinity. The LCPU oligomer exhibited thermotropic liquid crystalline properties between 166–183°C, and the smectic-A phase with focal conic fan textures at the liquid crystal state was observed by POM. The decomposition temperature of the LCPU oligomer at 5% weight loss was 282°C.

scholarly journals Chemical-Physical Characterization of a Binary Mixture of a Twist Bend Nematic Liquid Crystal with a Smectogen

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1110
Author(s):  
Abir Aouini ◽  
Maurizio Nobili ◽  
Edouard Chauveau ◽  
Philippe Dieudonné-George ◽  
Gauthier Damême ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystal ◽  
Liquid Crystalline ◽  
Smectic A ◽  
Liquid Crystalline Phases ◽  
Electro Optic ◽  
Optical Dielectric

Nematic twist-bend phases (NTB) are new types of nematic liquid crystalline phases with attractive properties for future electro-optic applications. However, most of these states are monotropic or are stable only in a narrow high temperature range. They are often destabilized under moderate cooling, and only a few single compounds have shown to give room temperature NTB phases. Mixtures of twist-bend nematic liquid crystals with simple nematogens have shown to strongly lower the nematic to NTB phase transition temperature. Here, we examined the behaviour of new types of mixtures with the dimeric liquid crystal [4′,4′-(heptane-1,7-diyl)bis(([1′,1″-biphenyl]4″-carbo-nitrile))] (CB7CB). This now well-known twist-bend nematic liquid crystal presents a nematic twist-bend phase below T ≈ 104 °C. Mixtures with other monomeric alkyl or alkoxy -biphenylcarbonitriles liquid crystals that display a smectic A (SmA) phase also strongly reduce this temperature. The most interesting smectogen is 4′-Octyl-4-biphenylcarbonitrile (8CB), for which a long-term metastable NTB phase is found at room and lower temperatures. This paper presents the complete phase diagram of the corresponding binary system and a detailed investigation of its thermal, optical, dielectric, and elastic properties.

scholarly journals Synthesis and Characterization of Lateral Fluoro-substituents Liquid Crystals

2021 ◽  
Vol 11 (5) ◽  
pp. 12495-12505
Keyword(s):  
Molecular Structure ◽  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Linkage Group ◽  
Optical Microscope ◽  
Synthesis And Characterization ◽  
Spectroscopic Techniques ◽  
Dielectric Measurements ◽  
Scanning Calorimetry

Lateral difluoro substituent liquid crystal based on a three-aromatic core has been synthesized. It has been designed to correlate the molecular structure and mesomorphism with reference to the difluoro substituent and -COO- linkage group. This compound was characterized by elementary analyses and spectroscopic techniques such as FTIR and 1H-NMR. The synthesis compound's mesomorphic behavior was studied by polarizing optical microscope, differential scanning calorimetry, and dielectric measurements. The recent investigation reveals only SmB phase.

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