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.

OPTICAL ACTIVITY AND LIGHT SCATTERING IN HIGHLY CHIRAL LIQUID CRYSTALS

1992 ◽  
Vol 06 (08) ◽  
pp. 425-446 ◽  
Author(s):  
PETER J. COLLINGS
Keyword(s):  
Liquid Crystals ◽  
Light Scattering ◽  
Optical Activity ◽  
Smectic A ◽  
Scattering Effects ◽  
Smectic A Phase ◽  
Blue Phases ◽  
Chiral Liquid Crystals

Theoretical and experimental optical activity and light scattering work in highly chiral liquid crystals is reviewed, starting from the early studies twenty years ago and ending with the most current investigations. Pretransitional effects in the isotropic and smectic A phases of highly chiral liquid crystals are discussed, as well as optical activity and light scattering effects in both the blue phases and smectic A * phase.

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.

EFFECT OF DYNAMIC CONFORMATION DISTRIBUTIONS ON MOLECULAR TILT IN CHIRAL SMECTIC LIQUID CRYSTALS

1991 ◽  
Vol 05 (12) ◽  
pp. 821-826
Author(s):  
SIN-DOO LEE ◽  
J. S. PATEL ◽  
J. W. GOODBY
Keyword(s):  
Liquid Crystals ◽  
Energy Barrier ◽  
Liquid Crystalline ◽  
Characteristic Temperature ◽  
Anomalous Behavior ◽  
Rotational Barrier ◽  
Smectic Liquid Crystals ◽  
Smectic A ◽  
Sign Inversion

It is shown that for some chiral smectic A materials the field-induced molecular tilt undergoes a peculiar sign inversion with respect to the layer normal as the temperature increases. The induced molecular tilt vanishes at a characteristic temperature in the smectic A state. This anomalous behavior can be described in terms of a dynamically fluctuating mixture of at least two molecular conformers, separated by an energy barrier in their liquid-crystalline states. The energy barrier between these two conformers is found to be comparable to the rotational barrier in normal hydrocarbons.

Electron Nuclear Double Resonance (ENDOR) Investigations of Organic Doublet Radicals in the Nematic and Smectic Phase of Liquid Crystals

1980 ◽  
Vol 34 (3) ◽  
pp. 305-310 ◽  
Author(s):  
B. Kirste ◽  
H. Kurreck
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Hyperfine Interactions ◽  
Double Resonance ◽  
Electron Nuclear Double Resonance ◽  
Smectic A ◽  
Smectic Phases ◽  
Anisotropic Hyperfine ◽  
Different Types ◽  
Nematic Phases

Different types of organic doublet radicals have been investigated in isotropic, nematic, and smectic phases of liquid crystals by performing electron nuclear double resonance (ENDOR), general TRIPLE and special TRIPLE experiments. For this purpose phenalenyls (perinaphthenyls), galvinoxyl, tetra- tert.-butylcarbazolyl, and bis(biphenylenyl)propenyl radicals have been chosen including some partially deuterated and 13C-labeled compounds. Anisotropic hyperfine interactions and deuterium quadrupole couplings could be determined. Smectic A phases have proved to be advantageous as compared to nematic phases in these studies. Detailed information about the orientation of the radicals within the liquid-crystalline solvent and about the conformations of the radicals could be obtained.

scholarly journals Methods for polymer-stabilization of molecular orientation in LC-waveguiding structures

2018 ◽  
Vol 10 (1) ◽  
pp. 11
Author(s):  
Katarzyna Agnieszka Rutkowska ◽  
Miłosz Chychłowski
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Light Propagation ◽  
Main Idea ◽  
Polymerization Process ◽  
Liquid Crystal Devices ◽  
Photo Polymerization ◽  
Polymer Liquid Crystals ◽  
Optical Applications ◽  
Liquid Crystalline Material

In this letter we present a new way for constructing and developing LC-based waveguiding structures. Specifically, liquid crystalline material enriched with monomer in the proper proportions is implemented in our approach and a waveguide geometry can be created in the LC cell thanks to the photo-polymerization process allowing for LC molecules to be suspended in desired position and orientation. The latter can be enforced by external fields and UV-irradiation can be performed trough the mask of desired geometry. In this way, regions with different molecular textures (e.g. planar and homeotropic) and thus waveguiding structures can be easily created within LC layer. The main idea of this letter is not only to show a prove-of-concept of the polymer-imposed LC stabilization for such planar optical devices but to discuss differences in methodology of their practical realization. Full Text: PDF ReferencesQ. Li, Liquid crystals beyond displays: chemistry, physics, and applications (John Wiley & Sons, 2012). CrossRef J.P. Lagerwall, G. Scalia, Current App. Phys. 12, 1387 (2012). CrossRef A. Ciferri, Polymer liquid crystals (Elsevier, 2012). DirectLink D. Yang, Fundamentals of liquid crystal devices (John Wiley & Sons, 2014). CrossRef L. Vicari, Optical applications of liquid crystals (CRC press, 2016). DirectLink I. Dierking, Adv Mater 12, 167 (2000). CrossRef K. Rutkowska, M. Chychłowski, M. Kwaśny, I. Ostromęcka, J. Piłka, U. Laudyn, "Light propagation in periodic photonic structures formed by photo-orientation and photo-polymerization of nematic liquid crystals", Opto-Electr. Rev. 25, 118 (2017). CrossRef K A. Rutkowska, M. Chychłowski, U.A. Laudyn, Proc. SPIE 10325, 1032506 (2017). CrossRef B. Turowski, K.A. Rutkowska, Phot. Lett. Poland 9, 82 (2017). CrossRef H. Ren, Y. Lin, S. Wu, Opt. Commun. 261, 296 (2006). CrossRef V. Mucci and C. Vallo, J Appl Polym Sci 123, 418 (2012). CrossRef U.A. Laudyn, M. Kwaśny, K. Jaworowicz, K.A. Rutkowska, M.A. Karpierz, G. Assanto, Phot. Lett. Poland 1, 7 (2009). CrossRef M.S. Chychłowski, S. Ertman, E. Nowinowski-Kruszelnicki, T.R. Woliński, Mol. Cryst. Liquid Cryst. 553, 127 (2012). CrossRef

Light-Scattering Characteristics in Smectic A Liquid Crystals

1991 ◽  
Vol 30 (Part 1, No. 5) ◽  
pp. 1038-1042 ◽  
Author(s):  
Nobuhiko Nawa ◽  
Dau Nuo
Keyword(s):  
Liquid Crystals ◽  
Light Scattering ◽  
Smectic A ◽  
Smectic A Liquid Crystals
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