scholarly journals In situ laser-imprinted surface realignment of a nematic liquid crystal

Soft Matter ◽  
2015 ◽  
Vol 11 (17) ◽  
pp. 3347-3353 ◽  
Author(s):  
Giorgio Mirri ◽  
Miha Škarabot ◽  
Igor Muševič
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystal ◽  
Nematic Liquid Crystals ◽  
New Method

We present a new method for the in-plane realignment of nematic liquid crystals in already fully assembled cells with uni-directionally rubbed polyimide as an aligning layer. This method can be applied to obtain twisted and planar μm-sized domains.

New structure induced by elastic anisotropy in cylindrical nematic liquid crystal

2017 ◽  
Vol 13 (2) ◽  
pp. 4705-4717
Author(s):  
Zhang Qian ◽  
Zhou Xuan ◽  
Zhang Zhidong
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystal ◽  
Elastic Anisotropy ◽  
Nematic Liquid Crystals ◽  
Gennes Theory

Basing on Landau–de Gennes theory, this study investigated the chiral configurations of nematic liquid crystals confined to cylindrical capillaries with homeotropic anchoring on the cylinder walls. When the elastic anisotropy (L2/L1) is large enough, a new structure results from the convergence of two opposite escape directions of the heterochiral twist and escape radial (TER) configurations. The new defect presents when L2/L1≥7 and disappears when L2/L1<7. The new structure possesses a heterochiral hyperbolic defect at the center and two homochiral radial defects on both sides. The two radial defects show different chiralities.

Orientation, interaction and laser assisted self-assembly of organic single-crystal micro-sheets in a nematic liquid crystal

Soft Matter ◽  
2015 ◽  
Vol 11 (38) ◽  
pp. 7674-7679 ◽  
Author(s):  
M. V. Rasna ◽  
K. P. Zuhail ◽  
U. V. Ramudu ◽  
R. Chandrasekar ◽  
J. Dontabhaktuni ◽  
...  
Keyword(s):  
Experimental Study ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Single Crystal ◽  
Nematic Liquid Crystal ◽  
Self Assembly ◽  
Nematic Liquid Crystals ◽  
Directed Assembly ◽  
Orientation Interaction ◽  
Organic Single Crystal

In this paper we report first experimental study on the orientation, interaction and directed-assembly of single crystal micro-sheets in nematic liquid crystals.

scholarly journals Beam splitting in chiral nematic liquid crystals

2018 ◽  
Vol 10 (4) ◽  
pp. 109
Author(s):  
Filip Sala
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystal ◽  
Soft Matter ◽  
Nematic Liquid Crystals ◽  
Beam Propagation Method ◽  
Beam Propagation ◽  
Optical Solitons ◽  
Molecular Reorientation ◽  
Chiral Nematic

By lunching the beam into the chiral nematic liquid crystals it is possible to achieve a non-diffractive beam similar to a soliton. This effect is caused by the molecular reorientation i.e. nonlinear response of the material forming the areas of higher refractive index. Diffraction is suppressed by the focusing effect. For appropriate launching conditions it is also possible to achieve a beam which splits into two or more separate beams. Such phenomenon is discussed in this article and analyzed theoretical. To model this effect Fully Vectorial Beam Propagation Method coupled with the Frank-Oseen elastic theory is used. Simulations are performed for various input beam powers, widths, polarization angles and launching positions. Full Text: PDF ReferencesG. Assanto and M. A. Karpierz, "Nematicons: self-localised beams in nematic liquid crystals", Liq. Cryst. 36, 1161–1172 (2009) CrossRef G. Assanto, Nematicons: Spatial Optical Solitons in Nematic Liquid Crystals, John Wiley & Sons Inc. Hoboken, New Jersey (2013) DirectLink A. Piccardi, A. Alberucci, U. Bortolozzo, S. Residori, and G. Assanto, "Soliton gating and switching in liquid crystal light valve", Appl. Phys. Lett. 96, 071104 (2010). CrossRef D. Melo, I. Fernandes, F. Moraes, S. Fumeron, and E. Pereira, "Thermal diode made by nematic liquid crystal", Phys. Lett. A 380, 3121 – 3127 (2016). CrossRef U. Laudyn, M. Kwaśny, F. A. Sala, M. A. Karpierz, N. F. Smyth, G. Assanto, "Curved optical solitons subject to transverse acceleration in reorientational soft matter", Sci. Rep. 7, 12385 (2017) CrossRef M. Kwaśny, U. A. Laudyn, F. A. Sala, A. Alberucci, M. A. Karpierz, G. Assanto, "Self-guided beams in low-birefringence nematic liquid crystals", Phys. Rev. A 86, 013824 (2012) CrossRef F. A. Sala, M. M. Sala-Tefelska, "Optical steering of mutual capacitance in a nematic liquid crystal cell", J. Opt. Soc. Am. B. 35, 133-139 (2018) CrossRef U. A. Laudyn, A. Piccardi, M. Kwasny, M. A. Karpierz, G. Assanto, "Thermo-optic soliton routing in nematic liquid crystals", Opt. Lett. 43, 2296-2299 (2018) CrossRef F. A. Sala, M. M. Sala-Tefelska, M. J. Bujok, J. "Influence of temperature diffusion on molecular reorientation in nematic liquid crystals", Nonlinear Opt. Phys. Mater. 27, 1850011 (2018) CrossRef I-C Khoo Liquid crystals John Wiley & Sons, Inc (2007) DirectLink P. G. de Gennes, J. Prost, The Physics of Liquid Crystals, Clarendon Press (1995) DirectLink U. A. Laudyn, P. S. Jung, M. A. Karpierz, G. Assanto, "Quasi two-dimensional astigmatic solitons in soft chiral metastructures", Sci. Rep. 6, 22923 (2016) CrossRef J. Beeckman, A. Madani, P. J. M. Vanbrabant, P. Henneaux, S-P. Gorza, M. Haelterman, "Switching and intrinsic position bistability of soliton beams in chiral nematic liquid crystals", Phys. Rev. A 83, 033832 (2011) CrossRef A. Madani, J. Beeckman, K. Neyts, "An experimental observation of a spatial optical soliton beam and self splitting of beam into two soliton beams in chiral nematic liquid crystal", Opt. Commun. 298–299, 222-226, (2013) CrossRef G. D. Ziogos, E. E. Kriezis, "Modeling light propagation in liquid crystal devices with a 3-D full-vector finite-element beam propagation method", Opt. Quant. Electron 40, 10 (2008) CrossRef F. A. Sala, M. A. Karpierz, "Chiral and nonchiral nematic liquid-crystal reorientation induced by inhomogeneous electric fields", J. Opt. Soc. Am. B 29, 1465-1472 (2012) CrossRef F. A. Sala, M. A. Karpierz, "Modeling of molecular reorientation and beam propagation in chiral and non-chiral nematic liquid crystals", Opt. Express 20, 13923-13938 (2012) CrossRef F. A. Sala, "Design of false color palettes for grayscale reproduction", Displays, 46, 9-15 (2017) CrossRef

scholarly journals Gradient theory of domain walls in thin, nematic liquid crystals films

2019 ◽  
Vol 22 (07) ◽  
pp. 1950063
Author(s):  
Marcel G. Clerc ◽  
Michał Kowalczyk ◽  
Panayotis Smyrnelis
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
External Field ◽  
Nematic Liquid Crystal ◽  
Domain Walls ◽  
Nematic Liquid Crystals ◽  
Gradient Theory ◽  
Crystal Sample ◽  
Bistable Region

In this paper, we describe domain walls appearing in a thin, nematic liquid crystal sample subject to an external field with intensity close to the Fréedericksz transition threshold. Using the gradient theory of the phase transition adapted to this situation, we show that depending on the parameters of the system, domain walls occur in the bistable region or at the border between the bistable and the monostable region.

Neutron Reflectometry-Based In Situ Structural Analysis of an Aligning Agent Additive for the Alignment of Nematic Liquid Crystals on Solid Substrates

Soft Matter ◽  
2022 ◽  
Author(s):  
Fumiya Nemoto ◽  
Norifumi L. Yamada ◽  
Masahiro Hino ◽  
Hiroyuki Aoki ◽  
Hideki Seto
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Structural Analysis ◽  
Nematic Liquid Crystals ◽  
Liquid Crystal Displays ◽  
Neutron Reflectometry ◽  
Initial Alignment ◽  
Solid Substrates

Surface aligning agents, such as amphiphilic surfactants, are widely used to control the initial alignment of nematic liquid crystals (NLCs) in liquid crystal displays (LCDs). Generally, these agents are first...

Structural evolution and dielectric properties of suspensions of carbon nanotubes in nematic liquid crystals

2017 ◽  
Vol 19 (25) ◽  
pp. 16456-16463 ◽  
Author(s):  
S. Tomylko ◽  
O. Yaroshchuk ◽  
O. Koval'chuk ◽  
N. Lebovka
Keyword(s):  
Carbon Nanotubes ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Dielectric Properties ◽  
Nematic Liquid Crystal ◽  
Nematic Liquid Crystals ◽  
Structural Evolution ◽  
Percolation Transition ◽  
Electrical Percolation

Smeared electrical percolation transition in suspensions of carbon nanotubes in nematic liquid crystal was revealed. Four stages of structural evolution were identified.

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.

A Novel Method for Measuring the Difference in Flexoelectric Coefficients of Nematic Liquid Crystals

2011 ◽  
Vol 181-182 ◽  
pp. 26-32
Author(s):  
Benjamin I. Outram ◽  
Steve J. Elston
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystal ◽  
Electric Fields ◽  
Nematic Liquid Crystals ◽  
Angle Of Incidence ◽  
Rotation Method ◽  
Twisted Nematic ◽  
Novel Method ◽  
The Difference

The difference between e1 and e3 parameters for flexoelectric polarization, as originally defined byMeyer, is measured for nematic liquid crystal materials E7 and BL087 in Twisted Nematic (TN) cells with In-Plane Switching (IPS) electric fields using the crystal rotation method, which measures transmission as a function of angle of incidence. Values of e1 − e3 for E7 and BL087 are found to be 7.2±1.0 pCm−1 and 9.4±1.0 pCm−1 respectively.

scholarly journals New linear solvation energy relationships for empirical solvent scales using the Kamlet–Abboud–Taft parameter sets in nematic liquid crystals

RSC Advances ◽  
2018 ◽  
Vol 8 (40) ◽  
pp. 22835-22845 ◽  
Author(s):  
Amid Ranjkesh ◽  
Meisam Hagh Parast ◽  
Olga Strzeżysz ◽  
Mohammad Sadegh Zakerhamidi ◽  
Tae-Hoon Yoon
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystal ◽  
Nematic Liquid Crystals ◽  
Solvation Energy ◽  
Linear Solvation Energy Relationships ◽  
Energy Relationships ◽  
Linear Solvation Energy ◽  
Linear Solvation

A new linear solvation energy relationships of empirical solvent scales with the Kamlet–Abboud–Taft parameters sets for nematic liquid crystal.

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