INFLUENCE OF THE FLOW ON THE ORIENTATION INDUCED BY A SOLID SUBSTRATE ON A NEMATIC LIQUID CRYSTAL

1992 ◽  
Vol 06 (03n04) ◽  
pp. 437-448 ◽  
Author(s):  
G. BARBERO ◽  
A. N. CHUVYROV ◽  
A. P. KREKHOV
Keyword(s):  
Experimental Data ◽  
Liquid Crystal ◽  
Simple Model ◽  
Nematic Liquid Crystal ◽  
Solid Substrate ◽  
Sample Thickness ◽  
Filling Process ◽  
Total Surface Energy ◽  
Surface Anchoring ◽  
Theoretical Results

The influence of the flow on the orientation induced by a solid substrate on a nematic liquid crystal is experimentally and theoretically analyzed. Our experimental data show that a nematic cell filled by capillarity presents a birefringence dependent on the sample thickness. This fact suggests that the symmetry of the problem is broken by the filling process. A simple model is presented in order to explain the experimental observations. According to this model, a surface anchoring contribution to the total surface energy, of the same order of the usual one appearing in the Rapini-Papoular expression, is connected to the flow. The agreement between the experimental data and the theoretical results is fairly good.

Temperature influence on homogeneous instabilities in stationary shear flow of nematic liquid crystal with weak surface anchoring

2010 ◽  
Vol 7 ◽  
pp. 191-201
Author(s):  
I.Sh. Nasibullayev ◽  
O.V. Urina
Keyword(s):  
Liquid Crystal ◽  
Shear Flow ◽  
Nematic Liquid Crystal ◽  
Effect Of Temperature ◽  
External Fields ◽  
Temperature Influence ◽  
Surface Anchoring ◽  
Weak Surface ◽  
Surface Coupling

Plane stationary shear flow of the nematic liquid crystal with weak surface anchoring is investigated. The effect of temperature, external fields, and the nature of the surface coupling on the formation of orientation instabilities is investigated.

Temperature influence on orientation dynamics of oscillatory Poiseuille flow of nematic liquid crystal

2010 ◽  
Vol 7 ◽  
pp. 172-181
Author(s):  
I.Sh. Nasibullayev ◽  
U.R. Kamaletdinova
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Poiseuille Flow ◽  
External Influence ◽  
Temperature Influence ◽  
Surface Anchoring ◽  
Orientation Behaviour ◽  
Orientation Change ◽  
Low Amplitude ◽  
Flow Plane

In this work is studying temperature influence and surface anchoring in orientation behaviour of oscillatory Poiseuille flow of nematic liquid crystal (NLC) in the plane cell. Without external influence molecules lays along flow plane. Molecules orientation change and caused by this back-flow is studied by low-amplitude decomposition.

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.

scholarly journals Coupling free energy and surface anchoring mechanism in gold nanorod–nematic liquid crystal dispersions

RSC Advances ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 4104-4111 ◽  
Author(s):  
Qi Wang ◽  
Liying Liu ◽  
Lei Xu
Keyword(s):  
Free Energy ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Gold Nanorod ◽  
Optical Birefringence ◽  
Surface Anchoring

Dependence of both the induced optical birefringence signals and simulated free energy ftotal with the pump H.

scholarly journals Optical Kossel Lines and Fluorescence in Photonic Liquid Crystals

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 541
Author(s):  
Vladimir A. Belyakov
Keyword(s):  
Experimental Data ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Light Absorption ◽  
Fluorescence Polarization ◽  
Direct Connection ◽  
X Ray ◽  
Optical Analog ◽  
Theoretical Results ◽  
Observation Results

We propose a general analytical way to describe the fluorescence peculiarities in photonic liquid crystals (revealing themselves as an optical analog of the X-ray Kossel lines in conventional crystals) based at the localized optical edge modes existing in perfect photonic liquid crystal layers. The proposed approach allows us to predict theoretically the properties of optical Kossel lines in photonic liquid crystal (fluorescence polarization, spectral and angular fluorescence distribution, influence of the light absorption in liquid crystal, and, in particular, existing the optical Borrmann effect if the absorption in liquid crystal is locally anisotropic). Comparison of the theoretical results and the known experimental data shows that the theory reproduces sufficiently well the observation results on the fluorescence in photonic liquid crystals. For confirming a direct connection of the optical Kossel lines to the localized optical edge modes in perfect photonic liquid crystal, we propose the application of time-delayed techniques in studying the optical Kossel lines.

scholarly journals Interference colors of nematic liquid crystal films at different applied voltages and surface anchoring conditions

2011 ◽  
Vol 19 (4) ◽  
pp. 3297 ◽  
Author(s):  
Yang Zou ◽  
Jun Namkung ◽  
Yongbin Lin ◽  
Dan Ke ◽  
Robert Lindquist
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Surface Anchoring ◽  
Liquid Crystal Films ◽  
Crystal Films

Determination of the unified surface-anchoring energy of a nematic liquid crystal on a polymer substrate

1998 ◽  
Vol 72 (3) ◽  
pp. 329-331 ◽  
Author(s):  
Akihiko Sugimura ◽  
Tetsuo Miyamoto ◽  
Makoto Tsuji ◽  
Michiyoshi Kuze
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Polymer Substrate ◽  
Surface Anchoring ◽  
Anchoring Energy
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