Pseudo-molecular approach for the elastic constants of nematic liquid crystals interacting via anisotropic dispersion forces

2014 ◽  
Vol 378 (4) ◽  
pp. 453-458 ◽  
Author(s):  
P.S. Simonário ◽  
F.C.M. Freire ◽  
L.R. Evangelista ◽  
R.T. Teixeira-Souza
Keyword(s):  
Liquid Crystals ◽  
Elastic Constants ◽  
Nematic Liquid Crystals ◽  
Dispersion Forces ◽  
Molecular Approach ◽  
Anisotropic Dispersion

Molecular structure and elastic constants of nematic liquid crystals

1979 ◽  
Vol 72 (2) ◽  
pp. 155-158 ◽  
Author(s):  
F. Leenhouts ◽  
A.J. Dekker ◽  
W.H. de Jeu
Keyword(s):  
Molecular Structure ◽  
Liquid Crystals ◽  
Elastic Constants ◽  
Nematic Liquid Crystals

A DYNAMICAL METHOD FOR DETERMINING THE ELASTIC CONSTANTS AND RELAXATION PARAMETERS IN NEMATIC LIQUID CRYSTALS

2000 ◽  
Vol 14 (04) ◽  
pp. 139-146 ◽  
Author(s):  
EMIL PETRESCU ◽  
CORNELIA MOTOC ◽  
DOINA MANAILA
Keyword(s):  
Magnetic Field ◽  
Liquid Crystals ◽  
Elastic Constants ◽  
Light Transmission ◽  
Nematic Liquid Crystals ◽  
Relaxation Parameters ◽  
Nematic Director ◽  
Dynamical Method ◽  
The Magnetic Field ◽  
Good Agreement

The theoretical model proposed by Pieranski et al.3 to describe the phenomena occurring in nematic liquid crystals when the magnetic field is suddenly varied was extended by considering higher powers of the distortion angle for the nematic director. Equations giving the time evolution of the number of extinctions in the light transmission were obtained. These equations depend on some relaxation parameters (the time constants τA and τB intervening when the magnetic field was switched "on" or "off", respectively) and on the ratio of elastic constants. The equations were solved numerically and good agreement with the experimental data was obtained for the nematic MBBA.

A correlation between short range smectic-like ordering and the elastic constants of nematic liquid crystals

1984 ◽  
Vol 45 (1) ◽  
pp. 157-162 ◽  
Author(s):  
M.J. Bradshaw ◽  
E.P. Raynes ◽  
I. Fedak ◽  
A.J. Leadbetter
Keyword(s):  
Liquid Crystals ◽  
Elastic Constants ◽  
Short Range ◽  
Nematic Liquid Crystals

Measurement of elastic constants of nematic liquid crystals with use of hybrid in-plane-switched cell

2012 ◽  
Vol 20 (3) ◽  
Author(s):  
E. Nowinowski-Kruszelnicki ◽  
J. Kędzierski ◽  
Z. Raszewski ◽  
L. Jaroszewicz ◽  
M. Kojdecki ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Magnetic Fields ◽  
Electric Field ◽  
Elastic Constants ◽  
Nematic Liquid Crystals ◽  
Experimental Tests ◽  
New Method ◽  
Dielectric Anisotropy ◽  
Main Concept

AbstractA new method for quick and pretty accurate measurements of splay, twist and bend elastic constants of nematic liquid crystals is experimentally verified. The main concept relies on exploiting only the electric field and determining magnitudes of nematic elastic constants from threshold fields for Freedericksz transitions in only one hybrid in-plane-switched cell. In such cell the deformations of an investigated liquid crystal are controlled by three separated pairs of electrodes confining measurement domains. In two of them inter-digital electrodes are mounted on one cell cover. Splay, twist and bend elastic constants can be measured by a proper choice of electrodes’ configuration together with orienting cover coatings (without applying magnetic fields). In this paper, we describe layout of our cells and results of experimental tests by using different liquid crystals: 5CB and 6CHBT (with positive dielectric anisotropy), Demus’ esters (with negative dielectric anisotropy) and new liquid crystals mixtures produced in our university.

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