Optical anisotropy, order parameter and its critical behavior in temperature-dependent refractive indices of nematic liquid crystals

2018 ◽  
Vol 268 ◽  
pp. 536-544 ◽  
Author(s):  
Amid Ranjkesh ◽  
Somaye Kiani ◽  
Olga Strzeżysz ◽  
Mohammad Sadegh Zakerhamidi ◽  
Tae-Hoon Yoon
Keyword(s):  
Liquid Crystals ◽  
Critical Behavior ◽  
Optical Anisotropy ◽  
Order Parameter ◽  
Nematic Liquid Crystals ◽  
Refractive Indices ◽  
Temperature Dependent

Order parameter and crossover temperature from temperature-dependent refractive indices for low birefringence liquid crystals

2017 ◽  
Vol 230 ◽  
pp. 280-289 ◽  
Author(s):  
Amid Ranjkesh ◽  
Jun-Chan Choi ◽  
Ji-Sub Park ◽  
Min-Kyu Park ◽  
Somaye Kiani ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Order Parameter ◽  
Refractive Indices ◽  
Crossover Temperature ◽  
Temperature Dependent

Order parameter of dual-frequency nematic liquid crystals measured over a wide range of thicknesses

2020 ◽  
Vol 47 (9) ◽  
pp. 1338-1344
Author(s):  
Olha Melnyk ◽  
Yuriy Garbovskiy ◽  
Anatoliy Glushchenko
Keyword(s):  
Liquid Crystals ◽  
Order Parameter ◽  
Nematic Liquid Crystals ◽  
Dual Frequency ◽  
Wide Range

Critical behavior in anchoring transitions of nematic liquid crystals

1990 ◽  
Vol 64 (16) ◽  
pp. 1911-1914 ◽  
Author(s):  
J. Bechhoefer ◽  
J-L. Duvail ◽  
L. Masson ◽  
B. Jérme ◽  
R. M. Hornreich ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Critical Behavior ◽  
Nematic Liquid Crystals ◽  
Anchoring Transitions

Study of optical parameters of two fluorinated isothiocyanato nematic liquid crystals exhibiting high birefringence

2014 ◽  
Vol 22 (1) ◽  
Author(s):  
T. Devi ◽  
B. Choudhury ◽  
A. Bhattacharjee ◽  
R. Dabrowski
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Laser Beam ◽  
Order Parameter ◽  
Refractive Indices ◽  
Optical Parameters ◽  
Optical Studies ◽  
High Birefringence ◽  
Two Samples ◽  
Direct Extrapolation

AbstractOptical studies have been carried out on two fluorinated isothiocyanato nematic liquid crystal (LC) compounds 4′-butylcyclohexyl-3, 5-difluoro-4-isothiocyanatobiphenyl and 4′-pentylcyclohexyl-3, 5-difluoro-4-isothiocynatobiphenyl. Transition temperatures of the two samples were confirmed using a polarizing microscope. The two LC compounds were found to exhibit fairly high clearing temperatures. Measurements of refractive indices of the two compounds were done by using thin prism method with He-Ne laser beam of wavelength 630 nm. Birefringence of the two LC compounds was calculated from the measured refractive indices. Both the compounds are found to display fairly high values of birefringence. Validation of a modified four-parameter model, based on Vuks equation describing the temperature dependence of refractive indices of the two liquid crystals, is also presented in this paper. The model is validated by fitting the experimentally measured values of refractive indices, birefringence and average refractive indices of the two nematic LCs with the theoretical values. In this paper, the calculation of order parameters of the LCs is presented by using two methods: direct extrapolation method based solely on the birefringence data and by using modified Vuks method based on Haller’s extrapolation. As observed from the obtained results, this procedure of calculating order parameter gives very reasonable results.

Renormalized Ellipsometry for Determining the Anisotropic Refractive Indices of Nematic Liquid Crystals

2003 ◽  
Vol 42 (Part 1, No. 2A) ◽  
pp. 486-491 ◽  
Author(s):  
Norihiko Tanaka ◽  
Mumehiro Kimura ◽  
Tadashi Akahane
Keyword(s):  
Liquid Crystals ◽  
Nematic Liquid Crystals ◽  
Refractive Indices

Molecular Ordering in Nematic MBCA and EPAPU

1990 ◽  
Vol 45 (1) ◽  
pp. 29-32
Author(s):  
S. Sreehari Sastry ◽  
V. Venkata Rao ◽  
P. Narayana Murty ◽  
G. Satyanandam ◽  
T. F. Sundar Raj
Keyword(s):  
Phase Transition ◽  
Liquid Crystals ◽  
Order Parameter ◽  
Nematic Phase ◽  
Spin Probe ◽  
Nematic Liquid Crystals ◽  
Experimental Techniques ◽  
First Order ◽  
Molecular Ordering

AbstractBy EPR, two nematic liquid crystals (MBCA and EPAPU) were investigated using a steroidal nitroxide spin probe. In both liquid crystals the isotropic-nematic phase transition is of first order. The observed variation of the order parameter with temperature is compared with predictions from the Maier-Saupe and Humphries-James-Luckhurst models and with results obtained by several other experimental techniques.

Optical properties of a liquid crystal with small ordinary and extraordinary refractive indices and small optical anisotropy

2014 ◽  
Vol 22 (3) ◽  
Author(s):  
J. Kędzierski ◽  
K. Garbat ◽  
Z. Raszewski ◽  
M. Kojdecki ◽  
K. Kowiorski ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Liquid Crystal ◽  
Optical Anisotropy ◽  
Order Parameter ◽  
Orientational Order ◽  
Refractive Indices ◽  
Orientational Order Parameter ◽  
Unknown Density ◽  
Abbe Refractometer

AbstractOptical properties of a nematic liquid crystal with small refractive index and small birefringence were studied. The ordinary and extraordinary refractive indices and birefringence were measured as functions of temperature by using an Abbe refractometer and wedge nematic cells. From values of these indices the nematic orientational order parameter was calculated by using several methods and corresponding mathematical models. Kuczyński et al. method was found to be suitable for determining the order parameter also for materials featuring small ordinary refractive index, with unknown density.

Effects of Conjugation of Mesogenic Core of Nematic Liquid Crystals for Polar Anchoring Energy and Surface Order Parameter on Rubbed Polyimide Films

1994 ◽  
Vol 33 (Part 2, No. 8B) ◽  
pp. L1174-L1177 ◽  
Author(s):  
Dae-Shik Seo ◽  
Norihiro Yoshida ◽  
Shunsuke Kobayashi ◽  
Michinori Nishikawa ◽  
Yoshikazu Yabe
Keyword(s):  
Liquid Crystals ◽  
Order Parameter ◽  
Nematic Liquid Crystals ◽  
Polyimide Films ◽  
Anchoring Energy
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