Fundamental Research on Development of Micro-Actuator Driven by Liquid Crystal

2012 ◽  
Vol 490-495 ◽  
pp. 3150-3154 ◽  
Author(s):  
Zhan Zhe Zhang ◽  
Gang Li
Keyword(s):  
Liquid Crystal ◽  
Constitutive Equation ◽  
Nematic Liquid Crystal ◽  
Applied Voltage ◽  
Liquid Crystalline ◽  
Parallel Plates ◽  
Micro Actuator ◽  
Fundamental Research ◽  
Micro Actuators

For the purpose of developing liquid crystalline micro-actuators, the transient behaviors of a nematic liquid crystal between two parallel plates have been computed for various parameters such as applied voltage, the gap between the plates, and the twist and tilt angles at the plates. The Leslie–Ericksen theory has been selected as a constitutive equation. As conclusion of this study, we can develop micro-actuators with arbitrary characteristics by suitably controlling the applied voltage, the size of the actuators, and the director anchoring conditions.

Fundamental Research on Development of Liquid Crystalline Micro-Actuator

2012 ◽  
Vol 502 ◽  
pp. 264-268 ◽  
Author(s):  
Chun Bo Liu ◽  
Yan Fang Guan
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Twist Angle ◽  
Parallel Plates ◽  
Micro Actuator ◽  
Plane Component ◽  
Out Of Plane ◽  
Calculation Results ◽  
Fundamental Research ◽  
Induced Flow

As a purpose of developing new micro-actuator driven by the liquid crystal flow, transient behaviors of a nematic liquid crystal between two parallel plates are computed with parameter of twist angle. The Frank and Leslie-Ericksen theory were used. When the twist angle is 0 deg, the induced flow is planar, and when the twist angle is not 0 deg, the flow has a out of plane component. The twist angle has little effect to the time characteristics of the flow. In the experiment, the applied voltage of 5 was used, and the results are in agreement with the calculation results.

Numerical Study on Liquid Crystalline Actuators Using Back-Flow Effect

2011 ◽  
Vol 211-212 ◽  
pp. 430-433
Author(s):  
Chun Bo Liu ◽  
Long Wang Yue ◽  
Xiao Xia Liu
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Liquid Crystalline ◽  
Numerical Study ◽  
Twist Angle ◽  
Parallel Plates ◽  
Plane Component ◽  
Out Of Plane ◽  
Induced Flow ◽  
Micro Actuators

As a purpose of developing micro-actuators driven by liquid crystals, transient behaviors of a nematic liquid crystal between two parallel plates under an electric field have investigated numerically by using the Leslie-Ericksen theory. Twist angle has been selected as computational parameters. Imposition of an electric field on a liquid crystal induces backflow whose profile and magnitude depend strongly on the twist angle of the director. When the twist angle is 0 degree, the induced flow is planar, and with increasing of the twist angle, the flow has an out of plane component, and finally the profile becomes unidirectional when the twist angle reaches 180 degrees.

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.

Bistable nematic liquid crystal device with flexoelectric switching

2006 ◽  
Vol 17 (4) ◽  
pp. 435-463 ◽  
Author(s):  
L. J. CUMMINGS ◽  
G. RICHARDSON
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Nematic Liquid Crystal ◽  
Liquid Crystal Display ◽  
Parallel Plates ◽  
Stable States ◽  
Numerical Work ◽  
Potential Applications ◽  
Simplifying Assumptions ◽  
Bistable Device

Motivated generally by potential applications in the liquid crystal display industry [8,35], and specifically by recent experimental, theoretical and numerical work [6,7,13,14,21,25,30,31], we consider a thin film of nematic liquid crystal (NLC), sandwiched between two parallel plates. Under certain simplifying assumptions, laid out in £2, we find that for monostable surfaces (i.e. only a single preferred director anchoring angle at each surface), two optically-distinct, steady, stable (equal energy) configurations of the director are achievable, that is, a bistable device. Moreover, it is found that the stability of both of these steady states may be destroyed by the application of a sufficiently large electric field, and that switching between the two states is possible, via the flexoelectric effect. Such a phenomenon could be used in NLC display devices, to reduce power consumption drastically. Previous theoretical demonstrations of such (switchable) bistable devices have either relied on having bistable bounding surfaces, that is, surfaces at which there are two preferred director orientations at the surface [7,14]; on having special (nonplanar) surface morphology within the cell that allows for two stable states (the zenithal bistable device (ZBD) [4,21], or, in the case of the Nemoptic BiNem technology [11,19], on flow effects and a very carefully applied electric field to effect the switching.

scholarly journals Diffraction and Polarization Properties of Electrically–Tunable Nematic Liquid Crystal Grating

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1929 ◽  
Author(s):  
Shuan-Yu Huang ◽  
Bing-Yau Huang ◽  
Chi-Chung Kang ◽  
Chie-Tong Kuo
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Electric Fields ◽  
Applied Voltage ◽  
Incident Beam ◽  
Electrode Structure ◽  
First Order ◽  
External Electric Fields ◽  
Order Diffraction ◽  
Liquid Crystal Grating

This work demonstrates an electrically-tunable nematic liquid crystal (NLC) diffraction grating with a periodic electrode structure, and discusses the polarization properties of its diffraction. The efficiency of the first-order diffraction can be gradually controlled by applying external electric fields cross the NLC, and the maximum diffraction efficiency of the first-order diffraction that can be obtained is around 12.5% under the applied voltage of 5.0 V. In addition to the applied electric field, the efficiency of the first-order diffraction can also vary by changing the polarized state of the incident beam. Antisymmetric polarization states with symmetrical intensities in the diffractions corresponding to the +1 and −1 order diffraction signals are also demonstrated.

Morphology of elastic nematic liquid crystal membranes

Soft Matter ◽  
2017 ◽  
Vol 13 (32) ◽  
pp. 5366-5380 ◽  
Author(s):  
Pardis Rofouie ◽  
Damiano Pasini ◽  
Alejandro D. Rey
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Liquid Crystalline ◽  
Cell Membranes ◽  
Biological Materials ◽  
Crystalline Phases ◽  
Liquid Crystalline Phases

Liquid crystalline phases found in many biological materials, such as actin, DNA, cellulose, and collagen can be responsible for the deformation of cell membranes.

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