Comparative dielectric and thermotropic properties of liquid crystalline polyesters as a function of mesogen group and flexible thioether group length

2003 ◽  
Vol 39 (9) ◽  
pp. 1875-1882 ◽  
Author(s):  
Paul Philippe Gilles ◽  
Jean Claude Milano ◽  
Jean Louis Vernet
Keyword(s):  
Liquid Crystalline ◽  
Thermotropic Properties

scholarly journals Oxadiazolyl-Pyridinium as Cationic Scaffold for Fluorinated Ionic Liquid Crystals

2021 ◽  
Vol 11 (21) ◽  
pp. 10347
Author(s):  
Melina S. Weber ◽  
Margit Schulze ◽  
Giuseppe Lazzara ◽  
Antonio Palumbo Piccionello ◽  
Andrea Pace ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Alkyl Chain ◽  
Scanning Calorimetry ◽  
New Class ◽  
Structural Variables ◽  
Ionic Liquid Crystals ◽  
Thermotropic Properties

The synthesis and characterization of a new class of 1,2,4-oxadiazolylpyridinium as a cationic scaffold for fluorinated ionic liquid crystals is herein described. A series of 12 fluorinated heterocyclic salts based on a 1,2,4-oxadiazole moiety, connected through its C(5) or C(3) to an N-alkylpyridinium unit and a perfluoroheptyl chain, differing in the length of the alkyl chain and counterions, has been synthesized. As counterions iodide, bromide and bis(trifluoromethane)sulfonimide have been considered. The synthesis, structure, and liquid crystalline properties of these compounds are discussed on the basis of the tuned structural variables. The thermotropic properties of this series of salts have been investigated by differential scanning calorimetry and polarized optical microscopy. The results showed the existence of an enantiotropic mesomorphic smectic liquid crystalline phase for six bis(trifluoromethane)sulfonimide salts.

Tuning the thermotropic properties of liquid crystalline p-substituted aroylhydrazones

RSC Advances ◽  
2015 ◽  
Vol 5 (55) ◽  
pp. 44274-44281 ◽  
Author(s):  
Hemant Kumar Singh ◽  
Sachin Kumar Singh ◽  
Rajib Nandi ◽  
Madan Kumar Singh ◽  
Vijay Kumar ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Smectic A ◽  
Thermotropic Properties

Lamellar smectic A to columnar mesophase crossover is observed in p-substituted aroylhydrazones by variation of the alkoxy chain density at peripherals.

Swallow-Tail Substituted Liquid Crystalline Perylene Bisimides: Synthesis and Thermotropic Properties

2009 ◽  
Vol 131 (40) ◽  
pp. 14442-14453 ◽  
Author(s):  
André Wicklein ◽  
Andreas Lang ◽  
Mathis Muth ◽  
Mukundan Thelakkat
Keyword(s):  
Liquid Crystalline ◽  
Perylene Bisimides ◽  
Thermotropic Properties

scholarly journals Thermotropic Behaviour of Liquid Crystalline Poly[n-(4’- cyanophenyl-4’’-phenoxy)alkyl acrylate] Gels in the Dry and Swollen States

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Richard Vendamme
Keyword(s):  
Liquid Crystalline ◽  
Crosslinking Density ◽  
The Other ◽  
Side Chain ◽  
Melting Transition ◽  
Spacer Length ◽  
Alkyl Acrylate ◽  
Molar Weight ◽  
Aliphatic Spacer ◽  
Thermotropic Properties

AbstractThis paper reports the thermotropic behaviour of various side-chain liquid crystalline (LC) networks and gels of poly[n-(4’-cyanophenyl-4’’-phenoxy)alkyl acrylate]. Increasing the aliphatic spacer length tend to increase the melting temperature of the pure LC polymers. On the other hand, increasing the crosslinking density lead to a decrease and broadening of the melting transition temperature. Swelling of a liquid crystalline elastomer in a low molar weight liquid crystal (LMWLC) leads to the formation of a LC gel, with thermotropic properties drastically different from the original LC polymers and solvents. The thermotropic behaviour of such an LC gel is determined by several parameters, such as the concentration of LMWLC inside the gel and the compatibility between the two types of mesogens.

Polymerizable liquid crystalline twin molecules: synthesis and thermotropic properties

2000 ◽  
Vol 27 (12) ◽  
pp. 1595-1611 ◽  
Author(s):  
Kathrin Kürschner ◽  
Peter Strohriegl
Keyword(s):  
Liquid Crystalline ◽  
Thermotropic Properties

Synthesis and Characterization of Biphenylnate Liquid Crystalline Polyurethanes

2010 ◽  
Vol 428-429 ◽  
pp. 158-161 ◽  
Author(s):  
Jian Feng Ban ◽  
Shao Rong Lu ◽  
Chen Xi Zhang
Keyword(s):  
Transition Temperature ◽  
Melting Point ◽  
Diethylene Glycol ◽  
Liquid Crystalline ◽  
Molar Ratio ◽  
Synthesis And Characterization ◽  
Flexible Chain ◽  
Ft Ir ◽  
Thermotropic Properties

A series of novel biphenylnate liquid crystalline polyurethanes (BLCPs) were synthesized by polyaddition reaction of 4,4’-dihydroxybiphenyl with 2,4-TDI(2,4-toluenediisocyanate) and diethylene glycol through changing the molar ratio of diphenol and diol. The thermotropic properties, the melting point (Tm) and the isotropization temperature (Ti) of the synthesized polyurethanes were characterized by FT-IR, DSC, POM and WXRD. The results of experiments showed that all of the polyurethane polymers exhibited thermotropic liquid crystalline properties between 130°C and 230°C. The transition temperature (Tm and Ti) decreased with an increase in the length of the flexible chain.

Synthesis and thermotropic properties of hydroxy and silyloxy axially substituted phthalocyanines

2000 ◽  
Vol 04 (05) ◽  
pp. 569-573 ◽  
Author(s):  
BELÉN DEL REY ◽  
M. VICTORIA MARTÍNEZ-DÍAZ ◽  
JOAQUÍN BARBERÁ ◽  
TOMÁS TORRES
Keyword(s):  
Liquid Crystalline ◽  
Room Temperature ◽  
Amorphous Structure ◽  
Axial Position ◽  
X Ray Diffraction ◽  
Polarizing Microscopy ◽  
X Ray ◽  
Temperature Range ◽  
Isotropic Materials ◽  
Thermotropic Properties

Novel boron(III) subphthalocyanines 5-8 with six lipophilic alkylthio chains at the peripheral sites, bearing hydroxy or triethylsilyloxy groups in the axial position, have been synthesized and their thermotropic properties have been studied. These compounds are gelatinous materials at room temperature and gradually soften as the temperature is raised up to a point at which high fluidity typical of classical liquids is observed. By the usual techniques employed for the study of thermotropic behaviour (polarizing microscopy, DSC and X-ray diffraction), no liquid crystalline properties have been found. Instead, the compounds have an amorphous structure (i.e. behave as isotropic materials) throughout the temperature range studied. They could be designated as liquid subphthalocyanines.

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