Principles and applications of cyclodextrin liquid crystals

2021 ◽  
Author(s):  
Martin Votava ◽  
Bart Jan Ravoo
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Host Molecules

Cyclodextrin-based liquid crystals combine the versatile properties of macrocyclic host molecules and liquid-crystalline mesophases.

Liquid-crystalline behaviour and electrorheological effect of phthalocyanine-based ionic liquid crystals

2020 ◽  
pp. 1-10
Author(s):  
Aikebaier Reheman ◽  
Shuangying Hu ◽  
Lianjun Cao ◽  
Danhua Xie ◽  
Guiyang Yan ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Electrorheological Effect ◽  
Ionic Liquid Crystals

Substrate induced freezing, melting and depinning transitions in two-dimensional liquid crystalline systems

2022 ◽  
Author(s):  
Bharti bharti ◽  
Debabrata Deb
Keyword(s):  
Molecular Dynamics ◽  
Liquid Crystals ◽  
Molecular Dynamics Simulations ◽  
Liquid Crystalline ◽  
Two Dimensional ◽  
One Dimensional ◽  
The One ◽  
Dynamics Simulations

We use molecular dynamics simulations to investigate the ordering phenomena in two-dimensional (2D) liquid crystals over the one-dimensional periodic substrate (1DPS). We have used Gay-Berne (GB) potential to model the...

Experimental and computational (DFT) studies on induced orthogonal smectic A∗ phase in hydrogen-bonded ferroelectric liquid crystals

2018 ◽  
Vol 32 (21) ◽  
pp. 1850223 ◽  
Author(s):  
P. Subhasri ◽  
R. Jayaprakasam ◽  
V. N. Vijayakumar
Keyword(s):  
Liquid Crystals ◽  
Molecular Orbital ◽  
Density Functional ◽  
Liquid Crystalline ◽  
Proton Acceptor ◽  
Dft Studies ◽  
Ferroelectric Liquid Crystals ◽  
Smectic A ◽  
Present Complex ◽  
Hydrogen Bonded

Hydrogen-bonded ferroelectric liquid crystals (HBFLC) are designed and synthesized from nonmesogenic chiral proton donor compound of (R)-([Formula: see text])-Methylsuccinic acid (MSA) and mesogenic proton acceptor compound of 4-undecyloxybenzoic acid (11OBA) in a different mole ratio. Intermolecular hydrogen bonds (H-bond) between the nonmesogenic and mesogenic compounds have been confirmed through experimental Fourier transform infrared spectroscopy (FTIR) and density functional theory (DFT) computational studies. The steric hindrance and inductive effects of the present complex and its influence on the structure are discussed. A rich phase polymorphism in the liquid crystalline complex has been studied using polarizing optical microscope (POM) and differential scanning calorimetry (DSC). The chiral phases observed in the present complex are due to the presence of lone pair (n) to anti-bonding ([Formula: see text]) transition symmetry which is validated by DFT studies. A noteworthy observation of induced smectic A[Formula: see text](Sm A[Formula: see text]) by quenching of traditional phase (nematic) has been identified and the reason for the same has been discussed by DFT studies. The unusual phase order of Sm A[Formula: see text], smectic C[Formula: see text](Sm C[Formula: see text]) and smectic G[Formula: see text][Formula: see text](Sm G[Formula: see text]) mesogenic phases are observed. The other liquid crystalline parameters are evaluated by experimental and theoretical calculations and the same has been compared. Increased tilt angle in liquid crystal (LC) molecules has been theoretically analyzed by natural bond orbital (NBO) studies. Stability of the HBFLC phases and its origination mechanism have been discussed with the help of highest occupied molecular orbital and lowest unoccupied molecular orbital (HOMO–LUMO) energies.

scholarly journals Influence of alkyl chain length and fluorine atoms substitution on infrared spectra of chiral liquid crystalline esters

2017 ◽  
Vol 66 (3) ◽  
pp. 63-74
Author(s):  
Anna Drzewicz ◽  
Marzena Tykarska ◽  
Magdalena Żurowska
Keyword(s):  
Molecular Structure ◽  
Infrared Spectroscopy ◽  
Liquid Crystals ◽  
Infrared Spectra ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Alkyl Chain ◽  
Alkyl Chain Length ◽  
Rigid Core ◽  
Helicoidal Structure

The infrared spectra were registered for series of three-ring liquid crystalline esters, differing in the structure of alkyl chain, in the substitution of benzene ring by fluorine atoms and in the type of helicoidal structure in the chiral smectic CA phase with antiferroelectric properties. The influence of molecular structure on the shift of signals coming from carbonyl group, located in the rigid core, was observed. Keywords: liquid crystals, helicoidal structure, chiral smectic CA phase, antiferroelectric crystalline phase, infrared spectroscopy

scholarly journals Temperature-Dependent X-Ray Studies of Discotic Hexagonal Columnar Mesophases in Trinuclear Gold(I) Pyrazolate Complex

2021 ◽  
Vol 17 (3) ◽  
pp. 285-294
Author(s):  
Mohamad Azani Abd Khadir Jalani ◽  
Hendrik O. Lintang ◽  
Siew Ling Lee ◽  
Juan Matmin ◽  
Nur Fatiha Ghazalli ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Variable Temperature ◽  
Gold Complex ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Heating And Cooling ◽  
Depth Study ◽  
Columnar Mesophases ◽  
Hexagonal Columnar

Gold(I) pyrazolate complex ([Au3Pz3]C10TEG) has been widely studied due to its interesting liquid crystalline properties by exhibiting the discotic hexagonal columnar arrangement. Generally, the liquid crystalline properties of the gold complex were confirmed based on their differential scanning calorimetry thermogram and polarized optical microscopy (POM) images. However, there is still no in-depth study on the phase transition in liquid crystals of [Au3Pz3]C10TEG especially on its structural change at variable temperature. In this study, the resulting liquid crystalline properties of [Au3Pz3]C10TEG upon being heated and cooled was extensively demonstrated via variable-temperature POM (VT-POM) and small angle X-ray scattering (VT-SAXS). Based on the VT-POM images, it was indicated that [Au3Pz3]C10TEG displayed a fan-shaped texture for typical arrangements of discotic hexagonal columnar of liquid crystals. Moreover, VT-SAXS results was in good agreement with the VT-POM images as it showed that [Au3Pz3]C10TEG might consist of two types of stacking system, which are ordered and disordered hexagonal discotic arrangements. Likewise, VT-SAXS analysis also demonstrated that hexagonal columnar mesophase of [Au3Pz3]C10TEG could be recovered even after the heating and cooling for two cycles.

scholarly journals Order Parameters, Orientational Distribution Functions and Heliconical Tilt Angles of Oligomeric Liquid Crystals

2019 ◽  
Author(s):  
Richard Mandle ◽  
John W. Goodby
Keyword(s):  
Phase Transition ◽  
Liquid Crystals ◽  
Tilt Angle ◽  
Order Parameter ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Thermal Evolution ◽  
Order Parameters ◽  
Distribution Functions ◽  
Orientational Distribution

We compare the order parameters, orientational distribution functions (ODF) and heliconical tilt angles of the TB phase exhibited by a liquid-crystalline dimer (CB7CB) to a tetramer (O47) and hexamer (O67) by SAXS/WAXS. Following the N-TB phase transition we find that all order parameters decrease, and while 〈P2 〉 remains positive 〈P4 〉 becomes negative. For all three materials the order parameter 〈P6 〉 is near zero in both phases. The ODF is sugarloaf-like in the nematic phase and volcano-like in the TB phase, allowing us to estimate the heliconical tilt angle of each material and its thermal evolution. The heliconical tilt angle appears to be largely independent of the material studied despite the differing number of mesogenic units.

Uv Curable Liquid Crystals and Their Application

1996 ◽  
Vol 425 ◽  
Author(s):  
H. Takatsu ◽  
H. Hasebe
Keyword(s):  
Liquid Crystals ◽  
Light Scattering ◽  
Liquid Crystalline ◽  
Room Temperature ◽  
Polymer Network ◽  
Driving Voltage ◽  
Uv Curable ◽  
Good Thermal Stability ◽  
Photo Polymerization ◽  
Smectic A

AbstractSome classes of liquid crystalline monoacrylates having no methylene spacers in a side chain have been prepared. The liquid crystalline monoacrylates have effects to reduce the driving voltage and the hysteresis for a light scattering display of Polymer Network liquid crystals prepared by photo-polymerization-induced phase separation.By photo-polymerization of a chiral monoacrylate monomer in a nematic liquid crystalline host including a black dichroic dye, a polarizer free reflective Spiral Polymer Aligned Nematic (SPAN) Guest Host (GH) LCD exhibiting a low driving voltage has been fabricated. The effect of the spiral polymers made of some kinds of chiral monoacrylates for a Super Twisted Nematic (STN) LCD using SPAN liquid crystals is discussed.UV-curable liquid crystals showing nematic phases at room temperature have been developed. By in situ photo-polymerization, the UV-curable liquid crystals can be utilized for the retardation film with high quality and good thermal stability. The fabrication of various kinds of retardation film using the UV-curable liquid crystals is discussed.UV-curable liquid crystals having isotropic-nematic-smectic A phase sequence have been developed and the photo-polymerization at the state of their uniaxially oriented smectic A phases at room temperature is discussed. The polymerized film is optically uniaxial and transparent without light scattering.

MOLECULAR ORIENTATION AND ELECTROHYDRODYNAMIC FLOW IN HOMOGENEOUS ER FLUIDS

2001 ◽  
Vol 15 (06n07) ◽  
pp. 973-979 ◽  
Author(s):  
HIROKI IWATSUKI ◽  
NAOTO GOHKO ◽  
HIROSHI KIMURA ◽  
YUICHI MASUBUCHI ◽  
JUN-ICHI TAKIMOTO ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Electric Field ◽  
Molecular Orientation ◽  
Liquid Crystalline ◽  
Polypropylene Glycol ◽  
Homogeneous Fluid ◽  
Immiscible Liquids ◽  
Electrohydrodynamic Flow ◽  
Er Fluids ◽  
Er Fluid

Homogeneous ER fluid is an ER fluid which consists of a homogeneous fluid only; it is neither a suspension nor a blend of immiscible liquids. Various liquid crystals are typical examples of homogeneous ER fluids. Recently, we have found that urethane-modified polypropylene glycol (UPPG) is one of the very few examples of homogeneous ER fluids which show no liquid crystalline order. In order to clarify the mechanism of the ER effect in this fluid, we have studied, in this paper, electrohydrodynamic flow under shear and electric field.

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