Synthesis and Mesomorphic Properties of Chiral Biphenylol Benzoates

1996 ◽  
Vol 425 ◽  
Author(s):  
Wan-Fang Lu ◽  
Zhi-Yong Zhang ◽  
Yong-Jia Shang
Keyword(s):  
Molecular Structure ◽  
Liquid Crystals ◽  
Phase Behavior ◽  
Liquid Crystalline ◽  
Smectic Liquid Crystals ◽  
Temperature Ranges ◽  
Mesomorphic Properties

AbstractTen new chiral liquid crystalline compounds I1–10 of 4′ -acyl-4-biphenylol (S) -4- (2-methyl-l-butoxy) benzoates were synthesized and their mesomorphic properties were tested. They are all smectic liquid crystals with wide temperature ranges and except for compounds I1, all exhibit a Sc*phase. The influence of molecular structure on phase behavior is discussed.

Design and electro-optic investigations of de Vries chiral smectic liquid crystals for exhibiting broad temperature ranges of SmA* and SmC* phases and fast electro-optic switching

2020 ◽  
Vol 8 (14) ◽  
pp. 4859-4868 ◽  
Author(s):  
V. Swaminathan ◽  
V. P. Panov ◽  
A. Panov ◽  
D. Rodriguez-Lojo ◽  
P. J. Stevenson ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Alkyl Chain ◽  
Smectic Liquid Crystals ◽  
Switching Speed ◽  
Temperature Range ◽  
Electro Optic ◽  
De Vries ◽  
Temperature Ranges

Two new ferroelectric liquid crystalline compounds using 5-phenyl-pyrimidine core terminated by achiral trisiloxane chain, and chiral (S) alkyl chain on the opposite ends of their respective mesogens are designed with better characteristics of switching speed and broader temperature range.

Synthesis and Mesomorphism of Novel Star-Shaped Liquid Crystals Containing Donor-Acceptor Groups

2013 ◽  
Vol 395-396 ◽  
pp. 72-75 ◽  
Author(s):  
Dan Shu Yao ◽  
Jun He ◽  
Guo Hua Li ◽  
Qian Xu ◽  
Ying Gang Jia ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Phase Behavior ◽  
Liquid Crystalline ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Chemical Structures ◽  
Thermogravimetric Analyzer ◽  
Liquid Crystalline Phases ◽  
Temperature Ranges ◽  
Donor Acceptor

A new class of three-armed star-shaped liquid crystals 5a-5d were synthesized, they used 1,3,5-trihydroxybenzene as a core, ω-[4-(p-ethoxybenzoloxy) phenoxycarbonyalkyl acid (3a, 3b) and ω-[4-(p-nitrobenzoloxy) phenoxycarbonyalkyl acid (3c, 3d) as mesogenic arms. Their chemical structures were confirmed by FTIR and 1H NMR spectra. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and thermogravimetric analyzer (TG) measurements. The results showed that the three-armed star-shaped liquid crystals exhibited a broad range of liquid crystalline phases at moderate temperature. The mesogenic arm structures obviously affected the phase behavior. As the intermedius alkyl chain of the star-shaped compounds lengthened (from n=4 to n=8), their melting points decreased but mesomorphic temperature ranges increased. The temperatures when 5% weight loss occurred (td) were higher than 300°C, which revealed that the synthesized three-armed liquid crystals had a high thermal stability. Threadlike, droplet and schlieren texture, typical of nematic phase can be observed in the liquid crystalline state during heating or cooling process.

Phase behavior in the reentrant-nematic region of chiral frustrated smectic liquid crystals

1998 ◽  
Vol 58 (1) ◽  
pp. 595-601 ◽  
Author(s):  
G. S. Iannacchione ◽  
C. W. Garland ◽  
J. Mieczkowski ◽  
E. Gorecka
Keyword(s):  
Liquid Crystals ◽  
Phase Behavior ◽  
Smectic Liquid Crystals

Effect of defects and surface anchoring on the phase behavior of chiral smectic liquid crystals

2016 ◽  
Vol 90 (3) ◽  
pp. 299-311 ◽  
Author(s):  
O. Riahi ◽  
F. Trabelsi ◽  
H. Dhaouadi ◽  
R. Zgueb ◽  
T. Othman
Keyword(s):  
Liquid Crystals ◽  
Phase Behavior ◽  
Smectic Liquid Crystals ◽  
Surface Anchoring

scholarly journals Influence of alkyl chain length and fluorine atoms substitution on infrared spectra of chiral liquid crystalline esters

2017 ◽  
Vol 66 (3) ◽  
pp. 63-74
Author(s):  
Anna Drzewicz ◽  
Marzena Tykarska ◽  
Magdalena Żurowska
Keyword(s):  
Molecular Structure ◽  
Infrared Spectroscopy ◽  
Liquid Crystals ◽  
Infrared Spectra ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Alkyl Chain ◽  
Alkyl Chain Length ◽  
Rigid Core ◽  
Helicoidal Structure

The infrared spectra were registered for series of three-ring liquid crystalline esters, differing in the structure of alkyl chain, in the substitution of benzene ring by fluorine atoms and in the type of helicoidal structure in the chiral smectic CA phase with antiferroelectric properties. The influence of molecular structure on the shift of signals coming from carbonyl group, located in the rigid core, was observed. Keywords: liquid crystals, helicoidal structure, chiral smectic CA phase, antiferroelectric crystalline phase, infrared spectroscopy

Synthesis and Mesomorphic Properties of New Liquid Crystalline Cyclohexyl-phenyl- and Dicyclohexyl-pyrimidines

1979 ◽  
Vol 34 (11) ◽  
pp. 1535-1541 ◽  
Author(s):  
Alois Villiger ◽  
Arthur Boiler ◽  
Martin Schadt
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Alkyl Chain ◽  
Viscosity Reduction ◽  
Refractive Indices ◽  
Thermal Compatibility ◽  
Chain Lengths ◽  
New Compounds ◽  
Mesomorphic Properties ◽  
End Group

Abstract Liquid Crystals, Cyclohexyl-phenyl-pyrimidines, Dicyclohexyl-pyrimidines The synthesis and mesomorphic properties of three new classes of cyano-substituted cyclohexyl-phenyl-and dicyclohexyl-pyrimidines are reported. The compounds are colourless, chemically and photochemically stable and have wide nematic mesophases. The thermal compatibility of the new compounds with other nematic liquid crystals is excellent. The large static positive dielectric anisotropics are shown to depend strongly on the position and number of hydrogenated rings as well as on the alkyl chain lengths within a homologous series. The reported bulk viscosities vary considerably among homologues. Hydrogenating the ring adjacent to the cyano end group causes η to increase, whereas a considerable viscosity reduction compared to nonhydrogenated homologues was found by hydrogenating the ring adjacent to the alkyl end group. The measured refractive indices of the new compounds are comparable to those of biphenyls.

EFFECT OF DYNAMIC CONFORMATION DISTRIBUTIONS ON MOLECULAR TILT IN CHIRAL SMECTIC LIQUID CRYSTALS

1991 ◽  
Vol 05 (12) ◽  
pp. 821-826
Author(s):  
SIN-DOO LEE ◽  
J. S. PATEL ◽  
J. W. GOODBY
Keyword(s):  
Liquid Crystals ◽  
Energy Barrier ◽  
Liquid Crystalline ◽  
Characteristic Temperature ◽  
Anomalous Behavior ◽  
Rotational Barrier ◽  
Smectic Liquid Crystals ◽  
Smectic A ◽  
Sign Inversion

It is shown that for some chiral smectic A materials the field-induced molecular tilt undergoes a peculiar sign inversion with respect to the layer normal as the temperature increases. The induced molecular tilt vanishes at a characteristic temperature in the smectic A state. This anomalous behavior can be described in terms of a dynamically fluctuating mixture of at least two molecular conformers, separated by an energy barrier in their liquid-crystalline states. The energy barrier between these two conformers is found to be comparable to the rotational barrier in normal hydrocarbons.

scholarly journals Perhydroazulene-based liquid-crystalline materials with smectic phases

2012 ◽  
Vol 8 ◽  
pp. 403-410 ◽  
Author(s):  
Zakir Hussain ◽  
Henning Hopf ◽  
S Holger Eichhorn
Keyword(s):  
Liquid Crystalline ◽  
X Ray Diffraction ◽  
Core System ◽  
Crystalline Materials ◽  
Smectic Phases ◽  
Differential Scanning Colorimetry ◽  
Temperature Ranges ◽  
Nematic Phases ◽  
Liquid Crystalline Materials ◽  
Mesomorphic Properties

New liquid-crystalline materials with a perhydroazulene core were synthesized and the stereochemistry of these compounds was investigated. The mesomorphic properties of the new LC compounds were investigated by differential scanning colorimetry, polarizing optical microscopy and X-ray diffraction. We report here on the LC properties of nonchiral materials, which predominantly exhibit smectic phases and display nematic phases only within narrow temperature ranges. The dependence of the mesogenic behavior of the new materials on the stereochemistry of the core system was also investigated. All newly synthesized compounds were fully characterized by the usual spectroscopic and analytical methods.

Synthesis and Properties of Side Chain Azobenzene Liquid Crystalline Polymers

2013 ◽  
Vol 781-784 ◽  
pp. 436-439
Author(s):  
Dan Shu Yao ◽  
Jun He ◽  
Hai Yan Wang ◽  
Mei Tian ◽  
Xiao Zhi He ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Graft Polymerization ◽  
Liquid Crystalline Polymers ◽  
Side Chain ◽  
Scanning Calorimetry ◽  
Crystalline Polymers ◽  
Chemical Structures ◽  
Thermogravimetric Analyzer ◽  
Temperature Ranges ◽  
Mesomorphic Properties

A series of new azobenzene side chain liquid crystalline polymers were synthesized by two different azo mesogen monomers, 4-((4-(ethoxycarbonyl) phenyl) diazenyl) phenyl 4-(allyloxy) benzoate (M1) and (4-((4-(ethoxycarbonyl) phenyl) diazenyl) phenoxy) methyl acetyl 4-(allyloxy) benzoate (M2). All polymers (P1~P8) were synthesized by graft polymerization using polymethyl hydrosiloxane as backbone. Their chemical structures were confirmed by FTIR and 1HNMR spectra. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and thermogravimetric analyzer (TG) measurements. The results showed that P1~P8 exhibited thermotropic liquid crystalline properties and revealed nematic thread texture with wide mesophase temperature ranges. The temperatures when 5% weight loss occurred were higher than 305°C, which declared that the synthesized azobenzene liquid crystalline polymers had a high thermal stability.

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