Helical twisting power and compatibility in twisted nematic phase of new chiral liquid crystalline dopants with various liquid crystalline matrices

Duda, Łukasz; Czajkowski, Maciej; Potaniec, Bartłomiej; Vaňkátová, Petra

doi:10.1080/02678292.2019.1599454

Cited by 12 publications

(9 citation statements)

References 31 publications

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“…The doping level of about 5% was chosen in order to introduce sufficient helical twisting power to observe twisted nematic phase textures under the microscope. For practical use, commercial chiral dopants as CB15 ( HTP ≈ 6–8 μm −1 ) [ 21 , 42 ] and S811 / R811 ( HTP ≈ 11 μm −1 ) [ 42 ] should be doped evenly at about 32% or 20%, respectively, to form selective reflection of light in the visible range.…”

Section: Resultsmentioning

confidence: 99%

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On the Miscibility of Nematic Liquid Crystals with Ionic Liquids and Joint Reaction for High Helical Twisting Power Product(s)

et al. 2021

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Mixtures of nematic liquid crystals (LCs) with chiral ionic liquids (CILs) may find application as active materials for electrically driven broadband mirrors. Five nematic liquid crystal hosts were mixed with twenty three ionic liquids, including chiral ones, and studied in terms of their miscibility within the nematic phase. Phase diagrams of the mixtures with CILs which exhibited twisted nematic phase were determined. Miscibility, at levels between 2 and 5 wt%, was found in six mixtures with cyanobiphenyl-based liquid crystal host—E7. On the other hand, the highest changes in the isotropization temperature was found in the mixtures with isothiocyanate-based liquid crystal host—1825. Occurrence of chemical reactions was found. A novel chiral binaphtyl-based organic salt [N11116][BNDP] was synthesized and, in reaction to the 1825 host, resulted in high helical twisting power product(s). Selectivity of the reaction with the isothiocyanate-based liquid crystal was found.

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Section: Resultsmentioning

confidence: 99%

“…[ 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. However, these examples should be treated as exceptions to the rule because lamellar smectic or columnar phases are preferred in most ionic liquid crystals [ 20 ], which, in turn, are not likely to mix with nematic LCs [ 21 ].…”

Section: Introductionmentioning

confidence: 99%

On the Miscibility of Nematic Liquid Crystals with Ionic Liquids and Joint Reaction for High Helical Twisting Power Product(s)

et al. 2021

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“…Межмолекулярная связь нематический ЖКхиральный допант также явилась предметом ряда экспериментальных исследований. Так, было обнаружено [68], что допирование ЖК веществами, склонными к образованию межмолекулярных Н-связей, приводит к некоторому увели-чению НТР и лучшей растворимости в нематической фазе.…”

Section: допанты с конфигурационной хиральностьюunclassified

Mechanisms of Chiral Transfer in Optically Active Dopant – Nematic Liquid Crystal Systems

Burmistrov¹,

Aleksandriiskii²,

Новиков³

et al. 2020

Liq. Cryst. and their Appl.

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Induction of helical mesophases by incorporating chiral dopants into the nematics matrix is the promising modern trends in the chemistry of liquid crystals. This process is associated with a unique phenomenon - an amplification of chirality in liquid-crystalline phases, which ensures the detection of enantiomers by their chiral induction, much more sensitive than other methods. The relevance of this approach is due to the need to create perspective electro-optical devices operating with ultra-low control voltages based on twist effects, chromatographic stationary phases with high chiral selectivity, flexible magnets, photo-sensitive nanostructures, and other smart LC materials. The successful solution of these problems is impossible without experimental research and theoretical comprehension of the mechanisms of third level chiral transfer optically active dopant – nematic liquid crystal. In the last decade, a large number of works have appeared on the solution of these problems. This review is devoted to a generalization of the experimental results and a theoretical description of the transfer of molecular chirality to orientationally ordered systems with the participation of both chiral molecular substituents with an asymmetric carbon atom and planar or quasi-planar fragments chirally distorted relative to each other. The stereochemical aspects of induction associated with the structural correspondences of the dopant and nematic liquid crystal, as well as the main classes of optically active additives, are discussed. Application of metal complexes, both Werner and macroheterocyclic, are presented. Special attention is paid to the results of the mechanisms study of chiral transfer due to various intermolecular interactions: hydrogen bonding, axial coordination, and the formation of inclusion compounds. The high efficiency of induction of spiral mesophases has been demonstrated with a combination of different self-assembly mechanisms in liquid crystal - chiral additive systems.

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“…In the past, CSP based on polysaccharides proved to be suitable for enantioseparation of various liquid crystals (LCs) by LC [11][12][13][14][15][16][17][18] and supercritical fluid chromatography (SFC) [19,20]. Recently, our group published study comparing enantioselective potential of several CSP for LCs in SFC environment and no other type of CSP matched the results of CSP based on amylose or cellulose [21].…”

Section: Introductionmentioning

confidence: 99%

How mobile phase composition and column temperature affect enantiomer elution order of liquid crystals on amylose tris(3‐chloro‐5‐methylphenylcarbamate) as chiral selector

2021

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A comprehensive study into the effects of mobile phase composition and column temperature on enantiomer elution order was conducted with a set of chiral rod‐like liquid crystalline materials. The analytes were structurally similar and comprised variances such as length of terminal alkyl chain, presence of chlorine, number of phenyl rings, and type of chiral center. Experiments were carried out in polar organic and reversed‐phase modes using amylose tris(3‐chloro‐5‐methylphenylcarbamate) immobilized on silica gel as the chiral stationary phase. For all liquid crystals, reversal of elution order of enantiomers was observed based on type of used cosolvent and/or its content in the mobile phase; for some of the liquid crystals a temperature‐induced reversal was also observed. Both linear and nonlinear dependencies of natural logarithm of enantioselectivity on temperature were found. Tested mobile phases comprised pure organic solvents and binary and tertiary mixtures of acetonitrile with organic solvents and/or water. Effect of acidic/basic mobile phase additives was also tested. Effect of structure of chiral selector is briefly discussed.

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Helical twisting power and compatibility in twisted nematic phase of new chiral liquid crystalline dopants with various liquid crystalline matrices

Cited by 12 publications

References 31 publications

On the Miscibility of Nematic Liquid Crystals with Ionic Liquids and Joint Reaction for High Helical Twisting Power Product(s)

On the Miscibility of Nematic Liquid Crystals with Ionic Liquids and Joint Reaction for High Helical Twisting Power Product(s)

Mechanisms of Chiral Transfer in Optically Active Dopant – Nematic Liquid Crystal Systems

How mobile phase composition and column temperature affect enantiomer elution order of liquid crystals on amylose tris(3‐chloro‐5‐methylphenylcarbamate) as chiral selector

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