scholarly journals Orientation of liquid crystalline materials by using carbon nanotubes

2011 ◽  
Vol 38 (1) ◽  
pp. 37-46 ◽  
Author(s):  
N.V. Kamanina ◽  
P.Ya Vasilyev ◽  
V.I. Studeonov

The solution of some problems, where the initial black field is necessary for the regime of light transmission through the electrooptical organic nematic liquid crystal structures has been considered via a homeotropic alignment of liquid crystal molecules on the substrate covered by carbon nanotubes. The results of this investigation can be used to develop optical elements for displays with vertical orientations of nematic liquid crystal molecules (for example, for MVA-display technology).

2011 ◽  
Vol 19 (1) ◽  
Author(s):  
J. Parka ◽  
M. Dąbrowski ◽  
R. Kowerdziej

AbstractThe liquid crystal technology is one of the most popular at the present time. To the most important parameters of liquid crystals belong optical anisotropy, viscosity, and twist elastic constants. One of the most difficult and problematic to measure parameters is a twist elastic constant K22. For new liquid crystalline materials, we have to characterize their physical properties, also a twist elastic constant K22.As a final result of this work, a twist elastic constant of new nematic liquid crystal materials was investigated. In this paper, a transmission-voltage characteristic of the in-plane switching cell was observed to find Freedericksz threshold, and then twist elastic constants could have been calculated. The method was checked on well-characterized materials E7 and 6-CHBT and its accuracy was better than 20%. In addition, the temperature dependence of K22 was determined for all materials.


2019 ◽  
Vol 43 (1-2) ◽  
pp. 67-77 ◽  
Author(s):  
Adil A Awad ◽  
Al-Ameen Bariz OmarAli ◽  
Ahmed Jasim M Al-Karawi ◽  
Zyad Hussein J Al-Qaisi ◽  
Samer Ghanim Majeed

{1-[4-( n-Alkoxy)]-2-(4’-decyloxy)benzylidene}hydrazines ( n-alkoxy = O(CH2) nH, n = 1–9, 12, 16 or 18), an asymmetrical series of 1,2-disubstituted hydrazines, were prepared in a simple two-step procedure as a part of our continuing work in evaluating hydrophobic azine compounds as photoluminescent liquid crystalline materials. The compounds were characterized spectroscopically and their liquid crystalline behaviour and luminescent properties were evaluated using polarized light optical microscopy, differential scanning calorimetry and X-ray powder diffraction techniques. The studies revealed that all of these compounds are liquid crystalline materials exhibiting photoluminescent properties in the crystalline and liquid crystal states.


2015 ◽  
Vol 3 (31) ◽  
pp. 7993-8005 ◽  
Author(s):  
Yafei Wang ◽  
Junwei Shi ◽  
Jianhua Chen ◽  
Weiguo Zhu ◽  
Etienne Baranoff

Fluorescent and phosphorescent liquid crystalline materials are reviewed with a focus on their application in polarised OLEDs.


2002 ◽  
Vol 74 (3) ◽  
pp. 493-509 ◽  
Author(s):  
Máximo Barón ◽  
R. F. T. Stepto

The document first gives definitions of basic terms related to liquid-crystalline and mesomorphic states of matter and then terms specific to the classification of liquid-crystal polymers. The terms have been restricted to those most commonly encountered in the structural description of the latter class of materials. The terms have been selected from the recently published comprehensive document "Definitions of basic terms relating to low-molar-mass and polymer liquid crystals" [Pure and Applied Chemistry73(5), 845-895 (2001)] and are intended to form a readily usable guide for the reader interested in the structural description of polymer liquid crystals. The more comprehensive document should be used for terminology associated with types of mesophases and the optical and physical characteristics of liquid-crystalline materials. The advice given by representatives of the International Liquid Crystal Society for the preparation of this document is gratefully acknowledged.


2015 ◽  
Vol 3 (5) ◽  
pp. 985-989 ◽  
Author(s):  
J. Guilleme ◽  
J. Aragó ◽  
E. Ortí ◽  
E. Cavero ◽  
T. Sierra ◽  
...  

The self-assembly of axial dipolar subphthalocyanine molecules in the presence of electric fields leads to uniaxially oriented columnar liquid crystalline materials that exhibit permanent polarization.


Author(s):  
W.S. Putnam ◽  
C. Viney

Many sheared liquid crystalline materials (fibers, films and moldings) exhibit a fine banded microstructure when observed in the polarized light microscope. In some cases, for example Kevlar® fiber, the periodicity is close to the resolution limit of even the highest numerical aperture objectives. The periodic microstructure reflects a non-uniform alignment of the constituent molecules, and consequently is an indication that the mechanical properties will be less than optimal. Thus it is necessary to obtain quality micrographs for characterization, which in turn requires that fine detail should contribute significantly to image formation.It is textbook knowledge that the resolution achievable with a given microscope objective (numerical aperture NA) and a given wavelength of light (λ) increases as the angle of incidence of light at the specimen surface is increased. Stated in terms of the Abbe resolution criterion, resolution improves from λ/NA to λ/2NA with increasing departure from normal incidence.


Author(s):  
Nanqi Bao ◽  
Jake Gold ◽  
Tibor Szilvasi ◽  
Huaizhe Yu ◽  
Robert Twieg ◽  
...  

Computational methods can provide first-principles insights into the thermochemistry and kinetics of reactions at interfaces, but this capability has not been widely leveraged to design soft materials that respond selectively...


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