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.

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.

scholarly journals Self-template–assisted micro-phase segregation in blended liquid-crystalline block copolymers films toward three-dimensional structures

2020 ◽  
Vol 117 (35) ◽  
pp. 21070-21078
Author(s):  
Yusuke Hibi ◽  
Yuki Oguchi ◽  
Yuta Shimizu ◽  
Kayoko Hashimoto ◽  
Katsuya Kondo ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Three Dimensional ◽  
Phase Segregation ◽  
Material Design ◽  
The Other ◽  
Cooling Process ◽  
Water Separation ◽  
Practical Applications ◽  
Out Of Plane ◽  
Fundamental Research

In-plane mesopatterns derived from block-copolymer (BCP) micro-phase segregation in thin films have attracted much interest in practical applications as well as fundamental research programs. However, phase segregation along the film-normal direction has been less studied. Here, we describe a strategy to concurrently, yet independently, control in-plane micro-phase and out-of-plane macro-phase segregation in multiblended films composed of liquid-crystalline BCPs (LCBCPs), affording spontaneously layered three-dimensional (3D) mesostructures. This strategy relies on sequential liquid crystallization during the cooling process in thermal annealing as follows. The constituent LCBCP with the highest isotropic-transition temperature (Tiso) first liquid-crystallizes and segregates from the other LCBCP mixture remaining in isotropic states to form a noncontaminated layer at the top surface. This preformed LCBCP layer preserves its inherent in-plane pattern and acts as a template guiding the subsequent micro-phase segregations of the other low-TisoLCBCPs underneath. This self-template–assisted micro-phase segregation (STAMPS) readily provides 3D mesostructures, the potential toward rational material design of which is also demonstrated in water-separation applications.

Switching and induced flow effects in chiral smectic C liquid crystals

1997 ◽  
Vol 8 (3) ◽  
pp. 263-270 ◽  
Author(s):  
GEORGE I. BLAKE ◽  
FRANK M. LESLIE ◽  
MIKE J. TOWLER
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
Boundary Conditions ◽  
Continuum Theory ◽  
Parallel Plates ◽  
Smectic C ◽  
Induced Flow ◽  
Flow Effects

We consider a chiral smectic C liquid crystal confined between parallel plates in the bookshelf geometry. Using a recently proposed continuum theory for such materials the behaviour of the cell is discussed when an electric field is applied and subsequently removed from the cell. We examine both symmetric and asymmetric boundary conditions for the director.

Magnetic out-of-plane component in MnAs/GaAs(001)

2003 ◽  
Vol 83 (14) ◽  
pp. 2850-2852 ◽  
Author(s):  
A. Ney ◽  
T. Hesjedal ◽  
C. Pampuch ◽  
J. Mohanty ◽  
A. K. Das ◽  
...  
Keyword(s):  
Plane Component ◽  
Out Of Plane

scholarly journals Design of Tunable Holographic Liquid Crystalline Diffraction Gratings

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6789
Author(s):  
Katarzyna A. Rutkowska ◽  
Anna Kozanecka-Szmigiel
Keyword(s):  
Liquid Crystal ◽  
Communication Networks ◽  
Optical Communication ◽  
Liquid Crystalline ◽  
Incident Light ◽  
Diffraction Gratings ◽  
Lagrange Equations ◽  
Experimental Conditions ◽  
Molecular Distribution ◽  
Polarization Gratings

Tunable diffraction gratings and phase filters are important functional devices in optical communication and sensing systems. Polarization gratings, in particular, capable of redirecting an incident light beam completely into the first diffraction orders may be successfully fabricated in liquid crystalline cells assembled from substrates coated with uniform transparent electrodes and orienting layers that force a specific molecular distribution. In this work, the diffraction properties of liquid crystal (LC) cells characterized by a continually rotating cycloidal director pattern at the cell substrates and in the bulk, are studied theoretically by solving a relevant set of the Euler-Lagrange equations. The electric tunability of the gratings is analyzed by estimating the changes in liquid crystalline molecular distribution and thus in effective birefringence, as a function of external voltage. To the best of our knowledge, such detailed numerical calculations have not been presented so far for liquid crystal polarization gratings showing a cycloidal director pattern. Our theoretical predictions may be easily achieved in experimental conditions when exploiting, for example, photo-orienting material, to induce a permanent LC alignment with high spatial resolution. The proposed design may be for example, used as a tunable passband filter with adjustable bandwidths, thus allowing for potential applications in optical spectroscopy, optical communication networks, remote sensing and beyond.

Characterization of some mesogenic alkyl 1-thioglycosides

2002 ◽  
Vol 80 (8) ◽  
pp. 1162-1165 ◽  
Author(s):  
B Henrissat ◽  
G K Hamer ◽  
M G Taylor ◽  
R H Marchessault
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Solid State ◽  
Solid State Nmr ◽  
Liquid Crystalline ◽  
Liquid Crystal Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Liquid Crystalline Phases

A series of dodecyl 1-thio-β-D-glycosides has been synthesized and characterized (DSC, NMR, CP MAS, X-ray diffraction) as possible new marking materials with liquid-crystalline properties. These compounds undergo solid to liquid crystal phase transitions at various temperatures, which depend on the nature of the carbohydrate part of the structure. Their liquid-crystalline phases show extreme shear thinning behaviour.Key words: liquid crystal, powder X-ray diffraction, phase transition, thioglycoside, solid-state NMR, marking material

scholarly journals Experimental and Computational Study of a Liquid Crystalline Dimesogen Exhibiting Nematic, Twist-Bend Nematic, Intercalated Smectic, and Soft Crystalline Mesophases

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 532
Author(s):  
Emily E. Pocock ◽  
Richard J. Mandle ◽  
John W. Goodby
Keyword(s):  
Liquid Crystalline ◽  
Computational Study ◽  
Structure Property ◽  
Correlation Lengths ◽  
Aspect Ratios ◽  
Smectic Phases ◽  
Out Of Plane ◽  
Lower Temperature ◽  
Soft Crystal ◽  
Optical Textures

Liquid crystalline dimers and dimesogens have attracted significant attention due to their tendency to exhibit twist-bend modulated nematic (NTB) phases. While the features that give rise to NTB phase formation are now somewhat understood, a comparable structure–property relationship governing the formation of layered (smectic) phases from the NTB phase is absent. In this present work, we find that by selecting mesogenic units with differing polarities and aspect ratios and selecting an appropriately bent central spacer we obtain a material that exhibits both NTB and intercalated smectic phases. The higher temperature smectic phase is assigned as SmCA based on its optical textures and X-ray scattering patterns. A detailed study of the lower temperature smectic ‘’X’’ phase by optical microscopy and SAXS/WAXS demonstrates this phase to be smectic, with an in-plane orthorhombic or monoclinic packing and long (>100 nm) out of plane correlation lengths. This phase, which has been observed in a handful of materials to date, is a soft-crystal phase with an anticlinic layer organisation. We suggest that mismatching the polarities, conjugation and aspect ratios of mesogenic units is a useful method for generating smectic forming dimesogens.

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