scholarly journals Polymer–Nematic Liquid Crystal Interface: On the Role of the Liquid Crystalline Molecular Structure and the Phase Sequence in Photoalignment

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 193
Author(s):  
Ameer R. K. Nassrah ◽  
István Jánossy ◽  
Viktor Kenderesi ◽  
Tibor Tóth-Katona
Keyword(s):  
Molecular Structure ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Conformational Changes ◽  
Liquid Crystalline ◽  
Three Dimensions ◽  
Phase Sequence ◽  
Photosensitive Polymer ◽  
Experimental Findings

We provide experimental evidence for the influence of the molecular structure of the nematic liquid crystal (NLC) on the photoalignment process in three dimensions at the interface with a polymer layer. In particular, the experimental findings are explained through the presence (or absence) of the π−π aromatic interactions between the NLC and the polymer. The influence of the nematic-to-smectic A phase transition on the photocontrol is also addressed. Furthermore, we demonstrate that the photo-induced reorientation scenarios can be eventually connected to conformational changes in the photosensitive polymer.

scholarly journals Mechanisms of Chiral Transfer in Optically Active Dopant – Nematic Liquid Crystal Systems

2020 ◽  
Vol 20 (4) ◽  
pp. 6-26
Author(s):  
V. A. Burmistrov ◽  
V. V. Aleksandriiskii ◽  
I. V. Novikov ◽  
O. I. Koifman
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
High Efficiency ◽  
Stationary Phases ◽  
Theoretical Description ◽  
Optically Active ◽  
Axial Coordination ◽  
Chiral Dopants

Induction of helical mesophases by incorporating chiral dopants into the nematics matrix is the promising modern trends in the chemistry of liquid crystals. This process is associated with a unique phenomenon - an amplification of chirality in liquid-crystalline phases, which ensures the detection of enantiomers by their chiral induction, much more sensitive than other methods. The relevance of this approach is due to the need to create perspective electro-optical devices operating with ultra-low control voltages based on twist effects, chromatographic stationary phases with high chiral selectivity, flexible magnets, photo-sensitive nanostructures, and other smart LC materials. The successful solution of these problems is impossible without experimental research and theoretical comprehension of the mechanisms of third level chiral transfer optically active dopant – nematic liquid crystal. In the last decade, a large number of works have appeared on the solution of these problems. This review is devoted to a generalization of the experimental results and a theoretical description of the transfer of molecular chirality to orientationally ordered systems with the participation of both chiral molecular substituents with an asymmetric carbon atom and planar or quasi-planar fragments chirally distorted relative to each other. The stereochemical aspects of induction associated with the structural correspondences of the dopant and nematic liquid crystal, as well as the main classes of optically active additives, are discussed. Application of metal complexes, both Werner and macroheterocyclic, are presented. Special attention is paid to the results of the mechanisms study of chiral transfer due to various intermolecular interactions: hydrogen bonding, axial coordination, and the formation of inclusion compounds. The high efficiency of induction of spiral mesophases has been demonstrated with a combination of different self-assembly mechanisms in liquid crystal - chiral additive systems.

The elastic and optical properties of a bent-core thiadiazole nematic liquid crystal: the role of the bend angle

2013 ◽  
Vol 1 (13) ◽  
pp. 2416 ◽  
Author(s):  
S. Kaur ◽  
L. Tian ◽  
H. Liu ◽  
C. Greco ◽  
A. Ferrarini ◽  
...  
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Bend Angle

Fast-response twisted nematic liquid crystal displays with ultrashort pitch liquid crystalline materials

2012 ◽  
Vol 39 (6) ◽  
pp. 715-720 ◽  
Author(s):  
Kohki Takatoh ◽  
Aya Harima ◽  
Yuya Kaname ◽  
Kazuya Shinohara ◽  
Mitsuhiro Akimoto
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Liquid Crystalline ◽  
Liquid Crystal Displays ◽  
Fast Response ◽  
Crystalline Materials ◽  
Twisted Nematic ◽  
Twisted Nematic Liquid Crystal ◽  
Liquid Crystalline Materials

The Role of Inertia and Dissipation in the Dynamics of the Director for a Nematic Liquid Crystal Coupled with an Electric Field

2015 ◽  
Vol 18 (1) ◽  
pp. 147-166 ◽  
Author(s):  
Peder Aursand ◽  
Johanna Ridder
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Nematic Liquid Crystal ◽  
Relative Strength ◽  
Inertial Forces ◽  
Director Field ◽  
Voltage Difference ◽  
Electrostatic Equilibrium ◽  
Variational Wave

AbstractWe consider the dynamics of the director in a nematic liquid crystal when under the influence of an applied electric field. Using an energy variational approach we derive a dynamic model for the director including both dissipative and inertial forces.A numerical scheme for the model is proposed by extending a scheme for a related variational wave equation. Numerical experiments are performed studying the realignment of the director field when applying a voltage difference over the liquid crystal cell. In particular, we study how the relative strength of dissipative versus inertial forces influence the time scales of the transition between the initial configuration and the electrostatic equilibrium state.

1219 Analysis of orientation behavior in liquid crystalline flow of nematic liquid crystal

2013 ◽  
Vol 2013.51 (0) ◽  
pp. _1219-1_-_1219-2_
Author(s):  
Takehiro TODA ◽  
Tomohiro TSUJI ◽  
Shigeomi CHONO
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Liquid Crystalline ◽  
Orientation Behavior

Role of different polarization mechanisms in the self-organization of the director of a thin layer of nematic liquid crystal

1997 ◽  
Vol 42 (5) ◽  
pp. 477-481
Author(s):  
Yu. K. Kornienko ◽  
A. P. Fedchuk
Keyword(s):  
Liquid Crystal ◽  
Thin Layer ◽  
Nematic Liquid Crystal ◽  
The Self ◽  
Self Organization

Influence of the molecular structure of components on the induction of mesophases in nematic liquid crystal systems

2007 ◽  
Vol 42 (1) ◽  
pp. 29-33 ◽  
Author(s):  
L. S. Bezhanova ◽  
Z. V. Baghdasaryan ◽  
M. L. Baburyan
Keyword(s):  
Molecular Structure ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal
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