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.

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.

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.

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.

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.

Molecular dynamics in weakly polar nematic liquid crystal doped with dye

2011 ◽  
Vol 89 (6) ◽  
pp. 661-665 ◽  
Author(s):  
Satya Prakash Yadav ◽  
Kamal Kumar Pandey ◽  
Abhishek Kumar Misra ◽  
Sudhaker Dixit ◽  
Rajiv Manohar
Keyword(s):  
Molecular Dynamics ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Intermolecular Interaction ◽  
Nematic Liquid Crystal ◽  
Molecular Orientation ◽  
Nematic Liquid Crystals ◽  
Dipole Interaction ◽  
Molecular Arrangement

Our intention in the present work is to find out the role of dye in the molecular orientation of the weakly polar nematic liquid crystal D6AOB. The doping of a dye introduces a disturbance in the molecular arrangement of the nematic liquid crystal molecules. However, this disturbance is found to be sensitive to the concentration of the dye dispersed in the nematic liquid crystal. It is found that orientation in the dyed nematic liquid crystal is less ordered than the orientation in the pure nematic liquid crystals. This behavior has been explained on the basis of intermolecular interaction, i.e., dipole–dipole interaction.

scholarly journals Expulsion of disclinations in nematic liquid crystals

2003 ◽  
Vol 14 (1) ◽  
pp. 39-59 ◽  
Author(s):  
PAOLO BISCARI ◽  
TIMOTHY J. SLUCKIN
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Boundary Conditions ◽  
Half Space ◽  
Nematic Liquid Crystal ◽  
Nematic Liquid Crystals ◽  
Critical Value ◽  
Repulsive Force ◽  
Anchoring Strength ◽  
Strong Anchoring

We study the interactions between a nematic liquid crystal disclination and the surface of the half-space which bounds it. When strong anchoring conditions are applied on the boundary, the biaxial core of the disclination affects the repulsive force that tends to drive the disclination away from the surface. If we replace the strong boundary conditions with an anchoring potential, the surface-disclination interaction depends on the surface extrapolation length. In particular, the nematic may expel the disclination if the anchoring strength is below a critical value.

scholarly journals Dual electrically and thermally responsive broadband reflectors based on polymer network stabilized chiral nematic liquid crystals: the role of crosslink density

2016 ◽  
Vol 52 (66) ◽  
pp. 10109-10112 ◽  
Author(s):  
Hitesh Khandelwal ◽  
Gilles H. Timmermans ◽  
Michael G. Debije ◽  
Albertus P. H. J. Schenning
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystal ◽  
Crosslink Density ◽  
Nematic Liquid Crystals ◽  
Polymer Network ◽  
Thermally Responsive ◽  
Chiral Nematic ◽  
Polymer Stabilized

An adjustable broadband reflector based on a polymer stabilized chiral nematic liquid crystal has been fabricated.

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