scholarly journals Identifying a Unique Communication Mechanism of Thermochromic Liquid Crystal Printing Ink

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 876
Author(s):  
Maja Strižić Jakovljević ◽  
Branka Lozo ◽  
Marta Klanjšek Gunde
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Intrinsic Property ◽  
Integrating Sphere ◽  
Thermochromic Liquid Crystal ◽  
Liquid Crystal Material ◽  
Communication Mechanism ◽  
Wide Range ◽  
And Control ◽  
Printing Ink

Thermochromic liquid crystal materials are commonly used in printing inks, opening up a wide range of possible applications. In order to ensure and control the most accurate application, the occurrence of the so-called colour play effect, i.e., the appearance of iridescent (rainbow) colours as a function of temperature, must be determined precisely. For this purpose, the temperature-dependent reflection of a sample must be measured using a spectrometer with an integrating sphere. The same values should be obtained for each sample containing the same thermochromic liquid crystalline material, irrespective of the spectrometer used, integrating sphere, layer thickness and the surface properties of the substrate. To describe this intrinsic property of the thermochromic liquid crystal material, the term communication mechanism might be considered. The research has shown how this mechanism is obtained experimentally.

scholarly journals Antiferroelectric Bent-Core Liquid Crystal for Possible High-Power Capacitors and Electrocaloric Devices

Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 652
Author(s):  
Rony Saha ◽  
Chenrun Feng ◽  
Alexey Eremin ◽  
Antal Jákli
Keyword(s):  
Liquid Crystal ◽  
High Power ◽  
Liquid Crystalline ◽  
Compound A ◽  
X Ray ◽  
Liquid Crystal Material ◽  
X Ray Scattering ◽  
Liquid Crystalline Structure ◽  
Sulfur Containing

We present small-angle X-ray scattering, polarized optical microscopy and electric current measurements of a sulfur-containing bent-core liquid crystal material for characterization of the layer and director structures, thermally and electrically driven transitions between antiferroelectric and ferroelectric structures and switching properties. It was found that the material has polarization-modulated homochiral synclinic ferroelectric (SmCsPFmod), homochiral anticlinic antiferroelectric (SmCaPA) and racemic synclininc antiferroelectric (SmCsPA) structures that can be reversibly switched between each other either thermally and/or electrically. High switching polarization combined with softness of the liquid crystalline structure makes this compound a good candidate for applications in high-power capacitors and electrocaloric devices.

Tunable topographical cellulose matrices for electro-optical liquid crystal cells

2006 ◽  
Vol 14 (4) ◽  
Author(s):  
I. Costa ◽  
P. Almeida ◽  
D. Filip ◽  
J. Figueirinhas ◽  
M. Godinho
Keyword(s):  
Thin Films ◽  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Cellulose Derivatives ◽  
Free Standing ◽  
Casting Technique ◽  
Solvent Vapour ◽  
Preparation Conditions ◽  
And Control ◽  
Crystal Cells

AbstractIn this work we have used acetoxypropylcellulose (APC) to produce free standing solid films (∼60 μm) that were used for assembling electro-optical devices. Thin films were obtained from concentrated lyotropic solutions of cellulose derivatives. Induced by the cast and shearing preparation conditions wrinkles and band textures can be observed in their free-surface plane. In order to eliminate and control these textures we used a process similar to that introducted in literature [1] which consists of storing the films in the same solvent-vapour atmosphere as the solution system. Lyotropic APC liquid crystalline solutions in dymethylacetamide (DMA) with crosslinker were prepared, thin films were obtained by using a shear/casting technique and stored in the solvent-vapour atmosphere until a planar structure was achieved. The dried crosslinked films were analyzed by optical polarised microscopy (POM) and scanning electron microscopy (SEM). The films with different topographies were used to produce optical cells composed by the cellulose derivative film covered on both free surfaces by a layer of the nematic liquid crystal E7 and placed between two transparent conducting substrates. The electro-optical properties of these cells were obtained.

Properties of ER Fluids Comprised of Liquid Crystalline Polymers

1999 ◽  
Vol 13 (14n16) ◽  
pp. 1966-1974 ◽  
Author(s):  
Akio Inoue ◽  
Yoichiroh Ide ◽  
Shyunji Maniwa ◽  
Hiroyuki Yamada ◽  
Hiroji Oda
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Liquid Crystalline ◽  
Morphological Changes ◽  
Particle Dispersion ◽  
Step Response ◽  
Large Temperature ◽  
Wide Range ◽  
Stress Curve ◽  
Generation Mechanisms

Side-chain liquid crystalline polysiloxanes (LCS) diluted with solvents show a large increase in viscosity and a newtonian flow under an electric field. Two types of solvent-diluted LCSs, A and B, are presented and their properties are described in this paper. Type A shows a large temperature-dependent ER effect a quick response of msec. order to an electric field and a dynamic behavior similar to that of a low molecular weight liquid crystal. Type B shows a stable ER effect throughout a wide range of temperatures up to 150°C, a two-step response of shear stress curve upon application of DC electric field and a micron-sized droplets structure which deforms with the electric field. The generation mechanisms of ER effect on the two types were discussed with the data of dynamic and morphological changes, referring those on a low molecular liquid crystal and a particle dispersion type ER fluid.

Numerical Analysis of the Liquid Crystalline Backflow-Driven Effect under a Continuous Square Wave Electric Field

2014 ◽  
Vol 609-610 ◽  
pp. 675-680
Author(s):  
Chun Bo Liu ◽  
An Biao Wang
Keyword(s):  
Liquid Crystal ◽  
Velocity Profile ◽  
Electric Field ◽  
Liquid Crystalline ◽  
Control Method ◽  
Plate Motion ◽  
Square Wave ◽  
Application Range ◽  
Drive And Control ◽  
And Control

In order to broaden the application range of liquid crystals, a new microfluidic drive and control method is proposed. Through a simulation model construction that links the plate motion and the liquid crystal backflow, we can study the coupling of the internal alignment and velocity fields of the liquid crystal in the model. On applying a continuous square wave electric field, the upper plate of the cell can be driven to move continuously, and the moving state can be related to the structure of the cell. When the gap between the two plates was 50 μm, the range of the change of tilt angle at the center of the cell was 6090°, and the induced backflow velocity profile was an S-shape. When the gap was 110 μm, because of the influence of the kickback effect, the range changed to 90100°, and the velocity profile was a double S-shape.

scholarly journals Liquid Crystal Thermography Measurement Uncertainty Analysis and Its Application to Turbulent Heat Transfer Measurements

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Yu Rao ◽  
Yamin Xu
Keyword(s):  
Heat Transfer ◽  
Liquid Crystal ◽  
Measurement Uncertainty ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Thermochromic Liquid Crystal ◽  
Turbine Blade Cooling ◽  
Liquid Crystal Thermography ◽  
Liquid Crystal Material ◽  
Nonintrusive Measurement

Liquid crystal thermography is an advanced nonintrusive measurement technique, which is capable of providing a high-accuracy continuous temperature field measurement, especially for a complex structured heat transfer surface. The first part of the paper presents a comprehensive introduction to the thermochromic liquid crystal material and the related liquid crystal thermography technique. Then, based on the aythors' experiences in using the liquid crystal thermography for the heat transfer measurement, the parameters affecting the measurement uncertainty of the liquid crystal thermography have been discussed in detail through an experimental study. The final part of the paper describes the applications of the steady and transient liquid crystal thermography technique in the study of the turbulent flow heat transfer related to the aeroengine turbine blade cooling.

Templated nanofiber synthesis via chemical vapor polymerization into liquid crystalline films

Science ◽  
2018 ◽  
Vol 362 (6416) ◽  
pp. 804-808 ◽  
Author(s):  
Kenneth C. K. Cheng ◽  
Marco A. Bedolla-Pantoja ◽  
Young-Ki Kim ◽  
Jason V. Gregory ◽  
Fan Xie ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Chemical Vapor ◽  
Low Concentrations ◽  
Wide Range ◽  
Crystalline Films ◽  
Organized Assemblies ◽  
Fibrous Polymer ◽  
Induced Changes ◽  
Lateral Organization

Extrusion, electrospinning, and microdrawing are widely used to create fibrous polymer mats, but these approaches offer limited access to oriented arrays of nanometer-scale fibers with controlled size, shape, and lateral organization. We show that chemical vapor polymerization can be performed on surfaces coated with thin films of liquid crystals to synthesize organized assemblies of end-attached polymer nanofibers. The process uses low concentrations of radical monomers formed initially in the vapor phase and then diffused into the liquid-crystal template. This minimizes monomer-induced changes to the liquid-crystal phase and enables access to nanofiber arrays with complex yet precisely defined structures and compositions. The nanofiber arrays permit tailoring of a wide range of functional properties, including adhesion that depends on nanofiber chirality.

scholarly journals Preparation and Aggregation-Induced Emission of New 1,3,5-Triazine-2,4,6-tricarboxamide with Liquid Crystal Properties

2018 ◽  
Vol 34 (4) ◽  
pp. 1741-1748 ◽  
Author(s):  
ABDULHAMID UMAR ◽  
MUSTAFFA SHAMSUDDIN
Keyword(s):  
Liquid Crystal ◽  
Solid State ◽  
Liquid Crystalline ◽  
Crystalline Material ◽  
Aggregation Induced Emission ◽  
Liquid Crystal Material ◽  
Crystal Properties ◽  
Thermal Data ◽  
Active Liquid ◽  
Liquid Crystalline Material

The combination of aggregation-induced emission (AIE) and liquid crystal properties generates solid-state efficient luminescent liquid crystal materials. Here in, we reported the synthesis of 1,3,5-triazine-2,4,6-tricarboxamide and utilized it as a supramolecular organic motif for the AIE-active liquid crystal material. The compound exhibits high-intensity emission maxima at 417 and 468 nm in the solid state with excitation at 254 nm, whereas it shows weak emission in the solution phase. Also, this compound behaves as liquid crystalline material and shows columnar hexagonal mesophase with endothermic peaks at 73.4oC, 185.6oC, and exothermic peaks were observed at 181.9oC and 66.1oC with focal conic fan shape texture. The thermal data showed that the compound is stable up to 200oC.

Triply-periodic nanostructures in surfactant, block copolymer, and biomembrane systems, and simulation of TEMs

1993 ◽  
Vol 51 ◽  
pp. 884-885
Author(s):  
David M. Anderson ◽  
Tomas Landh
Keyword(s):  
Liquid Crystalline ◽  
Diblock Copolymers ◽  
Cubic Phase ◽  
List Type ◽  
Interpenetrating Networks ◽  
Triply Periodic ◽  
Wide Range ◽  
Bicontinuous Cubic ◽  
Phase Liquid ◽  
Dividing Surface

First discovered in surfactant-water liquid crystalline systems, so-called ‘bicontinuous cubic phases’ have the property that hydropnilic and lipophilic microdomains form interpenetrating networks conforming to cubic lattices on the scale of nanometers. Later these same structures were found in star diblock copolymers, where the simultaneous continuity of elastomeric and glassy domains gives rise to unique physical properties. Today it is well-established that the symmetry and topology of such a morphology are accurately described by one of several triply-periodic minimal surfaces, and that the interface between hydrophilic and hydrophobic, or immiscible polymer, domains is described by a triply-periodic surface of constant, nonzero mean curvature. One example of such a dividing surface is shown in figure 5.The study of these structures has become of increasing importance in the past five years for two reasons:1)Bicontinuous cubic phase liquid crystals are now being polymerized to create microporous materials with monodispersed pores and readily functionalizable porewalls; figure 3 shows a TEM from a polymerized surfactant / methylmethacrylate / water cubic phase; and2)Compelling evidence has been found that these same morphologies describe biomembrane systems in a wide range of cells.

THE SOME QUESTIONS OF AUTONOMOUS MOTION AND MANAGEMENT OF LAND-MOBILE ROBOTIC COMPLEXES FOR UKRAINIAN GROUND FORCESE

2019 ◽  
pp. 53-58
Author(s):  
О. Кravchuk ◽  
V. Symonenkov ◽  
I. Symonenkova ◽  
O. Hryhorev
Keyword(s):  
Large Scale ◽  
Armed Forces ◽  
Distributed Information ◽  
Wide Range ◽  
Highly Effective ◽  
Information Management Systems ◽  
Robotic Devices ◽  
Principles And Standards ◽  
And Control ◽  
The Eu

Today, more than forty countries of the world are engaged in the development of military-purpose robots. A number of unique mobile robots with a wide range of capabilities are already being used by combat and intelligence units of the Armed forces of the developed world countries to conduct battlefield intelligence and support tactical groups. At present, the issue of using the latest information technology in the field of military robotics is thoroughly investigated, and the creation of highly effective information management systems in the land-mobile robotic complexes has acquired a new phase associated with the use of distributed information and sensory systems and consists in the transition from application of separate sensors and devices to the construction of modular information subsystems, which provide the availability of various data sources and complex methods of information processing. The purpose of the article is to investigate the ways to increase the autonomy of the land-mobile robotic complexes using in a non-deterministic conditions of modern combat. Relevance of researches is connected with the necessity of creation of highly effective information and control systems in the perspective robotic means for the needs of Land Forces of Ukraine. The development of the Armed Forces of Ukraine management system based on the criteria adopted by the EU and NATO member states is one of the main directions of increasing the effectiveness of the use of forces (forces), which involves achieving the principles and standards necessary for Ukraine to become a member of the EU and NATO. The inherent features of achieving these criteria will be the transition to a reduction of tasks of the combined-arms units and the large-scale use of high-precision weapons and land remote-controlled robotic devices. According to the views of the leading specialists in the field of robotics, the automation of information subsystems and components of the land-mobile robotic complexes can increase safety, reliability, error-tolerance and the effectiveness of the use of robotic means by standardizing the necessary actions with minimal human intervention, that is, a significant increase in the autonomy of the land-mobile robotic complexes for the needs of Land Forces of Ukraine.

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