scholarly journals Liquid Crystals Investigation Behavior on Azo-Based Compounds: A Review

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3462
Author(s):  
Nurul Asma Razali ◽  
Zuhair Jamain
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Intermediate Phase ◽  
Crystalline Solid ◽  
Structure Property ◽  
Isotropic Liquid ◽  
Daily Lives ◽  
Spacer Length ◽  
Ideal System ◽  
Electron Withdrawing Group

Liquid crystal is an intermediate phase between the crystalline solid and an isotropic liquid, a very common substance in our daily lives. Two major classes of liquid crystal are lyotropic, where a liquid crystal is dissolved in a specific solvent under a particular concentration and thermotropic, which can be observed under temperature difference. This review aims to understand how a structure of a certain azo compound might influence the liquid crystal properties. A few factors influence the formation of different liquid crystals: the length of the alkyl terminal chain, inter/intra-molecular interaction, presence of spacer, spacer length, polarization effects, odd-even effects, and the presence of an electron-withdrawing group or an electron-donating group. As final observations, we show the compound’s different factors, the other liquid crystal is exhibited, and the structure–property relationship is explained. Liquid crystal technology is an ideal system to be applied to products to maximize their use, especially in the electronic and medical areas.

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 Synthesis of organic liquid crystals containing selectively fluorinated cyclopropanes

2020 ◽  
Vol 16 ◽  
pp. 674-680 ◽  
Author(s):  
Zeguo Fang ◽  
Nawaf Al-Maharik ◽  
Peer Kirsch ◽  
Matthias Bremer ◽  
Alexandra M Z Slawin ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Thermodynamic Properties ◽  
Organic Liquid ◽  
Dielectric Anisotropy ◽  
Structure Property ◽  
Structure Property Relationships

This paper describes the synthesis of a series of organic liquid crystals (LCs) containing selectively fluorinated cyclopropanes at their termini. The syntheses used difluorocarbene additions to olefin precursors, an approach which proved straightforward such that these liquid crystal candidates could be efficiently prepared. Their physical and thermodynamic properties were evaluated and depending on individual structures, they either displayed positive or negative dielectric anisotropy. The study gives some guidance into effective structure–property relationships for the design of LCs containing selectively fluorinated cyclopropane motifs.

scholarly journals LIQUID CRYSTALS AND APPLICATIONS OF CHLOSTERIC LIQUID CRYSTAL IN LASER

2013 ◽  
Vol 22 ◽  
pp. 736-740 ◽  
Author(s):  
SURESH SONI ◽  
DIMPLE DHARNIYA BISHNOI ◽  
SUBHASH SONI ◽  
RAMSWROOP
Keyword(s):  
Mechanical Properties ◽  
Magnetic Properties ◽  
Liquid Crystals ◽  
Resonant Cavity ◽  
Crystalline Solid ◽  
Smectic Liquid Crystals ◽  
Isotropic Liquid ◽  
Electrical And Magnetic Properties ◽  
Chiral Nematic ◽  
State Of Matter

Liquid crystals are a state of matter intermediate between that of a crystalline solid and an isotropic liquid. They possess many of the mechanical properties of a liquid, e.g. - high fluidity, inability to support shear, formation, and coalescence of droplets. At the same time they are similar to crystals in that they exhibit anisotropy in their optical, electrical, and magnetic properties. We discuss some physical properties of nematic, cholesteric, and smectic liquid crystals (Specially focused on cholesteric) and some applications in laser due to Cholesteric Liquid Crystal’s resonant cavity which formed spontaneously and intrinsically, in the form of self-assembled chiral nematic helix.

The chemistry of liquid crystals

1983 ◽  
Vol 309 (1507) ◽  
pp. 77-92 ◽  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Physical Characteristics ◽  
Structure Property ◽  
Theoretical Concepts ◽  
Crystal State ◽  
Qualitative Understanding ◽  
Fluid Systems ◽  
Crystal Phases ◽  
Liquid Crystal Phases

The nature of the liquid crystal phases formed by different compounds and the thermal and other physical characteristics of these phases are strongly affected by the stereochemistry and structure of the molecules. Precise structure-property correlations of an embracing nature cannot yet be quantified, but even a qualitative understanding of such relations is desirable from many standpoints, including that of the achievement of still better liquid crystal materials for the ever widening range of applications that is emerging for these ordered but fluid systems. By means of a range of selected examples, an attempt is made to illustrate not only those areas where generalizations seem possible, but also others wherein the properties of the materials are much more difficult to understand, to such an extent that doubt must be cast on at least some theoretical concepts of the liquid crystal state.

scholarly journals Polymer selective laser curing for integrated optical switches

2017 ◽  
Vol 9 (1) ◽  
pp. 32
Author(s):  
Manuel Gil-Valverde ◽  
Manuel Cano-García ◽  
Rodrigo Delgado ◽  
Tianyi Zuo ◽  
José Manuel Otón ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Optical Switching ◽  
Optical Switch ◽  
Single Mode ◽  
Multimode Waveguide ◽  
Direct Writing ◽  
Isotropic Liquid ◽  
Direct Laser ◽  
Laser Curing

A simple in-layer electro optical switch has been prepared by selectively curing a photocurable optical polymer with a UV laser. The core of the device is a NOA-81 multimode waveguide grown by selective laser curing. The cladding is a positive calamitic liquid crystal, which allows tunability and switching of the waveguide by external driving electric signals. The effective refractive index in the guide changes upon switching the liquid crystal. Depending on the geometry, this setup leads to an electrooptical modulator or a switch between two levels of transmitted light. Full Text: PDF ReferencesT. Ako, A. Hope, T. Nguyen, A. Mitchell, W. Bogaerts, K. Neyts, and J. Beeckman, "Electrically tuneable lateral leakage loss in liquid crystal clad shallow-etched silicon waveguides", Opt. Express 23, 2846 (2015). CrossRef K. Kruse, C. Middlebrook, "Laser-direct writing of single mode and multi-mode polymer step index waveguide structures for optical backplanes and interconnection assemblies", Photon. Nanostruct. - Fundamentals and Appl. 13, 66 (2015). CrossRef A. Günther, A.B. Petermann, M. Rezem, M. Rahlves, M. Wollweber, and B. Roth, European Conf. Lasers and Electro-Optics - European Quantum Electronics Conference, Munich, Germany (2015).C. Florian, S. Piazza, A. Diaspro, P. Serra, M. Duocastella, "Direct Laser Printing of Tailored Polymeric Microlenses", ACS Appl. Mater. Interfaces, 8(27), 17028 (2016). CrossRef F. Costache, M. Blasl, "Optical switching with isotropic liquid crystals", Opt. Photonik 6, 29 (2011). CrossRef M. Cano-Garcia, R. Delgado, T. Zuo, M.A. Geday, X. Quintana, Jose M. Otón, 16th OLC Topical Meeting on the Optics of Liquid Crystals, Sopot, Poland (2015).S. Ishihara, H. Wakemoto, K. Nakazima, Y. Matsuo, "The effect of rubbed polymer films on the liquid crystal alignment", Liq. Cryst. 4(6), 669 (1989). DirectLink

Exposure and temperature dependences of contact angle of liquid crystals on photoaligning surface

2009 ◽  
Vol 17 (2) ◽  
Author(s):  
I. Gvozdovskyy ◽  
Yu. Kurioz ◽  
Yu. Reznikov
Keyword(s):  
Contact Angle ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Temperature Dependence ◽  
Nematic Liquid Crystal ◽  
Isotropic Liquid ◽  
Strong Light ◽  
Polymer Interface ◽  
Temperature Dependences ◽  
Homeotropic Orientation

AbstractWe report on first studies of wetting of liquid crystal on photoaligning surface. We observed strong light-induced variations of a contact angle of a liquid LC 5CB on a photoaligning surface of fluoro-polyvinyl-cinnamate (PVCN-F) and we connected these variations with changes of PVCN-F polarity. We also present drastic changes of the contact angle of a nematic liquid crystal (MLC-6080) on the PVCN-F surface in a vicinity of temperature anchoring transition of liquid crystal from homeotropic orientation to planar one. We did not find any peculiarities in temperature dependence of the contact angle of isotropic liquid (glycerol) on PVCN-F and of nematic liquid crystal on pure glass in the same temperature range. It allows us to suggest that rearrangement of LC molecules and flexible fragments in the LC-polymer interface are responsible for the change of surface tensions both of LC and polymer and the observed jump of the contact angle.

Research on Non-Electric Readout Infrared Thermal Imaging Detection Technology Based on the Liquid Crystal

2011 ◽  
Vol 181-182 ◽  
pp. 293-296
Author(s):  
Chang Long Cai ◽  
Ya Zhang ◽  
Xiao Ling Niu ◽  
Wei Guo Liu
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Thermal Imaging ◽  
Optical Rotation ◽  
Cholesteric Liquid Crystals ◽  
Isotropic Liquid ◽  
Infrared Thermal Imaging ◽  
Detection Technology ◽  
Imaging Detection

Liquid crystal, as a condensed matter, is a phase state between crystal and isotropic liquid. On the one hand, it has mobility and continuity as a liquid, and on the other hand, it has arranging ordering as a crystal, then it has many unique properties. Because the factors, such as heat, electric field, magnetic field, pressure, and so on, will easily influence the arranging of liquid crystal molecular, so once it is excited externally, its optical properties will be changed. At present, most research on the theory and application of liquid crystal mainly focus on the display. Thermo-optic effect is defined as the phenomenon that the optical properties of liquid crystal change with the changing of temperature. At the phase transition point, the thermo-optic effect of liquid crystal is very obvious. In this paper, non-electric readout infrared thermal imaging detection technology based on the optical rotation property of the cholesteric liquid crystals is mainly researched. Through the research, the cholesteric liquid crystals’ light curves, gray value curves and CCD image were obtained under different temperatures; it proved that using the optical rotation property of cholesteric liquid crystals to achieve the infrared imaging of hot objects is possible.

P-142: High Performance Optically Isotropic Liquid Crystal Display using Twisted Liquid Crystals for Flexible LCDs

2018 ◽  
Vol 49 (1) ◽  
pp. 1699-1702
Author(s):  
Seong Min Song ◽  
Srinivas Pagidi ◽  
Hyesun Yoo ◽  
Chang Suk Lee ◽  
Young Jin Lim ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
High Performance ◽  
Liquid Crystal Display ◽  
Isotropic Liquid

Phase transitions and fluidity characteristics of lipids and cell membranes

1975 ◽  
Vol 8 (2) ◽  
pp. 185-235 ◽  
Author(s):  
D. Chapman
Keyword(s):  
Phase Transitions ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Living Cell ◽  
Molecular Orientation ◽  
Liquid Crystalline ◽  
Crystalline Solid ◽  
Living Tissue ◽  
Liquid Crystal Phase ◽  
Different Types

The concept that the liquid crystalline or mesomorphic condition was of importance to biological systems is a relatively old idea. Thus Bernal (1933) when discussing the different types of arrangements of molecules in liquid crystals commented ‘Such structures belong to the liquid crystal as a unit and not to its molecules which may be replaced by others without destroying them and they persist in spite of the complete fluidity of the substance. These are just the properties to be required for a degree of organization between that of the continuous substance, liquid or crystalline solid and even the simplest living cell.’ Stewart (1961) some thirty years later also stated that ‘It is this property – the combination of flow and lability with a preferred and relatively stable molecular orientation – that makes the mesomorphic (i.e. liquid crystal) phase uniquely appropriate to the structure of protoplasm and living tissue.’

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