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...

Determination and Analysis of the Physical Properties of a New Class of Polar Nematic Liquid Crystals

1985 ◽  
Vol 40 (9) ◽  
pp. 932-943 ◽  
Author(s):  
Hp. Schad ◽  
S. M. Kelly
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Physical Properties ◽  
Nematic Liquid Crystals ◽  
Mean Field ◽  
Liquid Crystal Displays ◽  
Aromatic Ketones ◽  
New Class ◽  
Twisted Nematic ◽  
Continuum Theories

Abstract We have measured the physical properties of three homologues of a new class of polar nematic liquid crystals having no molecular association. On the basis of mean field and continuum theories an analysis of the physical properties has been performed. The advantageous application of this class of compounds (substituted aromatic ketones) in liquid crystal displays - especially in the highly multiplexed twisted nematic display - is outlined and an example of a simple practical mixture is given.

Pattern Formation in Electrohydrodynamic Convection

MRS Bulletin ◽  
1991 ◽  
Vol 16 (1) ◽  
pp. 46-56 ◽  
Author(s):  
Walter Zimmermann
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Pattern Formation ◽  
Electric Field ◽  
Organic Molecules ◽  
Nematic Liquid Crystals ◽  
Liquid Crystal Displays ◽  
Director Field ◽  
Axis Orientation ◽  
Fundamental Research

One hundred years after their discovery, we meet liquid crystals everywhere in our daily life. Their most widely known application is the liquid crystal displays (LCDs) in watches, pocket calculators, or gasoline pumps. Applications aside, liquid crystals show many exciting properties, making them highly interesting for fundamental research. For example, electrohydrodynamic convection (EHC) in nematic liquid crystals, which is studied in cells of a configuration similar to liquid crystal displays, serves with its characteristic properties as a model System for investigating central questions of pattern formation and chaos.Today's liquid crystal displays work on the principle described in 1971 by Martin Schadt and Wolfgang Helfrich (Figure 1). In nematic liquid crystals, organic molecules orient on average along a macroscopic direction, described by the director field n(r), that has neither head nor tail (n = −n). Nematics are therefore anisotropic and for energetic reasons, n(r) orients parallel (perpendicular) to an electric field when the dielectric permittivity (ε∥) along n is larger (smaller) than the perpendicular (ε⊦ one. For positive εa = ε∥ − ε⊦, when an electric field is applied perpendicular to the direction of n, a reorientation of n takes place together with a corresponding change in the optical property of the cell. The controlled change by an electric field in the optic axis (orientation) in well-defined areas of the display then allows the representation of numbers, etc.

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.

scholarly journals Nanocomposites of Polyaniline and Cellulose Nanocrystals Prepared in Lyotropic Chiral Nematic Liquid Crystals

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Dawei Zhang ◽  
Lihong Zhang ◽  
Bingzhe Wang ◽  
Guangzhe Piao
Keyword(s):  
Liquid Crystals ◽  
Cellulose Nanocrystals ◽  
Nematic Liquid Crystals ◽  
Weight Ratio ◽  
Asymmetric Reaction ◽  
Reaction Field ◽  
Electron Microscopies ◽  
Chiral Nematic ◽  
Before And After

Stable lyotropic chiral nematic liquid crystals (N*-LCs) of cellulose nanocrystals (CNs) were prepared via hydrolysis using sulfuric acid. The lyotropic N*-LCs were used as an asymmetric reaction field to synthesize polyaniline (PANI) onto CNs by in situ polymerization. As a primary step, we examined the mesophase transition of the N*-LCs of CNs suspension before and after in situ polymerization of aniline (ANI) by polarizing optical microscopy. The structure of nanocomposites of PANI/CNs was investigated at a microscopic level using Fourier transform infrared spectroscopy and X-ray diffraction. Influence of the CNs-to-ANI ratio on the morphology of the nanocomposites was also investigated at macroscopic level by scanning electron and transmission electron microscopies. It is found that the weight ratio of CNs to aniline in the suspension significantly influenced the size of the PANI particles and interaction between CNs and PANI. Moreover, electrical properties of the obtained PANI/CNs films were studied using standard four-probe technique. It is expected that the lyotropic N*-LCs of CNs might be available for an asymmetric reaction field to produce novel composites of conjugated materials.

Optically isotropic liquid crystal media formulated by doping star-shaped cyclic oligosiloxane liquid crystal surfactants in twin nematic liquid crystals

Soft Matter ◽  
2015 ◽  
Vol 11 (19) ◽  
pp. 3772-3779 ◽  
Author(s):  
Namil Kim ◽  
Dae-Yoon Kim ◽  
Minwook Park ◽  
Yu-Jin Choi ◽  
Soeun Kim ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystals ◽  
Isotropic Liquid

The formation of an optically isotropic liquid crystal (LC) medium by doping the star-shaped LC molecular surfactant in a nematic LC medium may allow us to develop new electro-optical LC devices.

scholarly journals Dual wavelength in situ photoalignment for stable planar alignment of nematic liquid crystals

2018 ◽  
Vol 8 (8) ◽  
pp. 2366 ◽  
Author(s):  
Vineet Kumar ◽  
Aboozar Nasrollahi ◽  
Vijay Kumar Baliyan ◽  
Heung-Shik Park ◽  
Myong-Hoon Lee ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Nematic Liquid Crystals ◽  
Dual Wavelength

An in-plane switching liquid crystal cell with weakly anchored liquid crystals on the electrode substrate

2017 ◽  
Vol 5 (18) ◽  
pp. 4384-4387 ◽  
Author(s):  
O. Sato ◽  
N. Iwata ◽  
J. Kawamura ◽  
T. Maeda ◽  
Y. Tsujii ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Liquid Crystal Displays ◽  
Polyimide Film ◽  
Liquid Crystal Cell ◽  
Crystal Cell ◽  
Hexyl Methacrylate ◽  
The One

We present the “one-side zero-anchoring in-plane switching” (OZ-IPS) mode in liquid crystal displays (LCDs) comprising an electrode substrate onto which poly(hexyl methacrylate) chains are grafted and a counter substrate coated with a rubbed polyimide film.

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