scholarly journals Nematic Structures under Conical Anchoring at Various Director Tilt Angles Specified by Polymethacrylate Compositions

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2993
Author(s):  
Denis A. Kostikov ◽  
Mikhail N. Krakhalev ◽  
Oxana O. Prishchepa ◽  
Victor Ya. Zyryanov
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Tilt Angle ◽  
Oblique Incidence ◽  
Light Polarization ◽  
Polymer Mixture ◽  
Two Component ◽  
Field Action ◽  
Optical Textures ◽  
Crucial Parameter

Dependence of the director tilt angle of nematic liquid crystal (LC) under conical anchoring from the two-component polymer mixture composition has been studied. We varied the ratio of poly(isobutyl methacrylate) (PiBMA), which specifies a conical anchoring for the nematic liquid crystal LN-396, and poly(methylmethacrylate) (PMMA) assigning a tangential alignment for the same nematic. An oblique incidence light technique to determine a tilt angle has been used. It has been shown that the tilt angle increases from 0∘ to 47.7∘ when PiBMA:PMMA ratio changes in the range 30:70 to 100:0. The specific optical textures viewed under the polarizing microscope and proper orientational structures have been considered for various compositions of the polymer films. An electric field action on the formed orientational structures has been investigated. The obtained results are promising for the application in various electro-optical LC devices with a conical anchoring in which the director tilt angle is a crucial parameter: a controlled diffraction gratings, an electrically operated achromatic rotators of linear light polarization, etc.

ON AN ORIENTATION TRANSITION IN NEMATIC LIQUID CRYSTALS INDUCED BY THE THICKNESS OF THE SAMPLE

1993 ◽  
Vol 07 (18) ◽  
pp. 1215-1222
Author(s):  
A. L. ALEXE-IONESCU
Keyword(s):  
Experimental Data ◽  
Phase Transitions ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Tilt Angle ◽  
Critical Thickness ◽  
Large Range ◽  
Square Root ◽  
Chiral Molecules ◽  
Homeotropic Orientation

An orientation transition observed in nematic liquid crystal samples, induced by the thickness, is interpreted in a new way. By supposing that the nematic liquid crystal contains chiral impurities, it is shown that the homeotropic orientation is stable only for thicknesses smaller than a critical one, and is dependent on the concentration of the chiral molecules. At the critical thickness, the transition from the homeotropic orientation to the distorted one is characterized by a tilt angle proportional to the square root of the actual thickness minus the critical one. This trend is typical of second order phase transitions. The agreement between the theory and the experimental data is fairly good over a large range of thickness of the sample.

Tilt Angle Generation for Nematic Liquid Crystal on Blended Homeotropic Polyimide Layer Containing Trifluoromethyl Moieties

2003 ◽  
Vol 42 (Part 1, No. 4A) ◽  
pp. 1713-1714 ◽  
Author(s):  
Jeoung-Yeon Hwang ◽  
Seung Hee Lee ◽  
Seung Kwon Paek ◽  
Dae-Shik Seo
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Tilt Angle ◽  
Polyimide Layer

Effect of the Polymer Tilt Angle for Generation of Pretilt Angle in Nematic Liquid Crystal on Rubbed Polyimide Surfaces

1995 ◽  
Vol 34 (Part 2, No. 4B) ◽  
pp. L503-L506 ◽  
Author(s):  
Dae-Shik Seo ◽  
Kazuo Araya ◽  
Norihiro Yoshida ◽  
Michinori Nishikawa ◽  
YoshikazuYabe ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Tilt Angle ◽  
Pretilt Angle

scholarly journals Modeling Reorientation Dynamics of Electrically Assisted Light-Induced Gliding of Nematic Liquid-Crystal Easy Axis

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
S. V. Pasechnik ◽  
A. V. Dubtsov ◽  
D. V. Shmeliova ◽  
D. A. Semerenko ◽  
V. G. Chigrinov ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Nematic Liquid Crystal ◽  
Easy Axis ◽  
Uv Light ◽  
Light Polarization ◽  
Balance Model ◽  
Polarization Azimuth ◽  
Electrically Assisted ◽  
Reorientation Dynamics

The phenomenological torque balance model previously introduced to describe the electrically assisted light-induced gliding is generalized to study the reorientation dynamics of the nematic liquid crystal easy axis at photoaligned azo-dye films under the combined action of in-plane electric field and reorienting UV light linearly polarized at varying polarization azimuth,φp. We systematically examine the general properties of the torque balance model by performing analysising the bifurcations of equilibria at different values of the polarization azimuth and apply for the model to interpret the experimental results. These involve observation of the pronounced purely photoinduced reorientation atφp≠0, as opposed to the case where the light polarization vector is parallel to the initial easy axis (φp=0), and the reorientation is almost entirely suppressed. In the regions between electrodes with nonzero electric field, the effects described by the model are that (a) the dynamics of reorientation slows down withφpand (b) the sense of easy axis rotation is independent of the sign ofφp.

Refractive index matched half-wave plate with a nematic liquid crystal for three-dimensional laser metrology applications

2016 ◽  
Vol 24 (4) ◽  
Author(s):  
W. Piecek ◽  
L.R. Jaroszewicz ◽  
E. Miszczyk ◽  
Z. Raszewski ◽  
M. Mrukiewicz ◽  
...  
Keyword(s):  
Refractive Index ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Twist Angle ◽  
Three Dimensional ◽  
Light Polarization ◽  
Half Wave Plate ◽  
Wave Plate ◽  
Half Wave ◽  
Laser Metrology

AbstractThere exists a need in a quality and accuracy of a three-dimensional laser metrology operating in numerically controlled automatic machines. For this purpose, one sends three laser beams mutually perpendicular. These three beams of the wavelength λ = 0.6328 μm are generated by the same laser and are directed along three independent, orthogonal, mutually perpendicular, optical paths with a given light polarization plain. Using these beams, constituting the frame of coordinates, three independent laser rangefinders are able to determine spatial coordinates of a working tool or a workpiece. To form these optical pulses, a special refractive index matched Half-Wave Plate with nematic Liquid Crystal (LCHWP) was applied. The presented half-wave plate is based on a single Twisted Nematic (TN) cell (with the twist angle

Properties of two-component nematic liquid crystal mixtures in the range of 0.3–3.0 THz

2015 ◽  
Vol 42 (9) ◽  
pp. 1243-1249 ◽  
Author(s):  
Urszula Chodorow ◽  
Olga Chojnowska ◽  
Janusz Parka
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Two Component
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