Temperature dependences of the electrooptical properties of rodlike nematic liquid crystals doped with hockey-stick-shaped liquid crystals

2016 ◽  
Vol 68 (2) ◽  
pp. 264-267 ◽  
Author(s):  
Sunggu Yeo ◽  
Anoop Kumar Srivastava ◽  
Hyojin Lee ◽  
Ji-Hoon Lee ◽  
E.-Joon Choi
Keyword(s):  
Liquid Crystals ◽  
Nematic Liquid Crystals ◽  
Hockey Stick ◽  
Temperature Dependences ◽  
Electrooptical Properties

scholarly journals Investigation of the dielectric parameters of nematic liquid crystals in the boundary layers

2020 ◽  
Vol 61 (3) ◽  
pp. 43-48
Author(s):  
Guzal A. Gaisina (Mukhamedyarova) ◽  
◽  
Ayrat D. Galimbekov ◽  
Keyword(s):  
Dielectric Constant ◽  
Liquid Crystals ◽  
Boundary Layers ◽  
Nematic Liquid Crystals ◽  
Thick Layer ◽  
Bulk Sample ◽  
Isotropic Phase ◽  
Dielectric Parameters ◽  
Temperature Dependences ◽  
Nematic Phases

This article presents the results of a study of the dielectric properties of thin liquid crystal layer systems. To study the dielectric parameters of nematic liquid crystals in the boundary layers, the frequency and temperature dependences of the real (ε') and imaginary (ε'') parts of the dielectric constant were determined. We studied samples that are in macroscopic layers and samples located in flat capillary layers (d ~ 0.1 μm). In both cases, the measurement is performed by the same method, namely, the method of temporary dielectric spectroscopy. The entire procedure for measuring, recording, accumulating and processing data was carried out automatically. In this case, the results of dielectric measurements could be presented both in the frequency and time domains. For measurements, a plane-parallel measuring cell made of brass and titanium electrodes was used. It should be noted that the surface of a solid body has a strong influence on the phase state of liquids and liquid crystals in the boundary layer. For example, in such a layer, liquid molecules acquire a mesophase ordering. In the case of NLC, the nematic potential increases and, as a result, the temperature of the nematic-isotropic phase transition increases. However, a shift in the bleaching temperature in the NLC mixture studied by us did not appear due to the smallness of the effect. The substance enclosed in the microspace between the surfaces of the mica has a higher dielectric constant than the corresponding bulk sample. Moreover, such a difference is observed both in the isotropic and in the nematic phases. This can be explained as follows. In a thick layer, a dipole-dipole intermolecular interaction takes place, which reduces the effective dipole moment of the molecules.

FREQUENCY AND TEMPERATURE DEPENDENCES OF PERMITTIVITY AND LOSS TANGENT OF SOME NEMATIC LIQUID CRYSTALS

2014 ◽  
pp. 223-237 ◽  
Author(s):  
R.G. Rachmatullina ◽  
V.S. Gorelov ◽  
V.A. Timofeev ◽  
A.F. Aminova ◽  
A.M. Fattachova ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Loss Tangent ◽  
Nematic Liquid Crystals ◽  
Temperature Dependences

The electrohydrodynamic instability in twisted nematic liquid crystals

1994 ◽  
Vol 4 (2) ◽  
pp. 239-252 ◽  
Author(s):  
A. Hertrich ◽  
A. P. Krekhov ◽  
O. A. Scaldin
Keyword(s):  
Liquid Crystals ◽  
Nematic Liquid Crystals ◽  
Electrohydrodynamic Instability ◽  
Twisted Nematic

Surface disclinations in nematic liquid crystals

1975 ◽  
Vol 36 (1) ◽  
pp. 59-67 ◽  
Author(s):  
V. Vitek ◽  
M. Kléman
Keyword(s):  
Liquid Crystals ◽  
Nematic Liquid Crystals
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