Functional Photochromic Methylhydrosiloxane‐Based Side‐Chain Liquid‐Crystalline Polymers

Tóth-Katona, Tibor; Cigl, Martin; Fodor‐Csorba, Katalin; Hamplová, Věra; Jánossy, I.; Kašpar, Miroslav; Vojtylová, Terézia; Hampl, František; Bubnov, Alexej

doi:10.1002/macp.201300729

Cited by 40 publications

(25 citation statements)

References 50 publications

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“…Both polymers contain the same azobenzene chromophore having two lateral methyl substituents in ortho ‐positions close to the azo‐bond. As was shown before, these substituents provide improvement of the light sensitivity with comparison with non‐substituted analogues and significant stability of the photoinduced Z ‐form of the chromophores; back thermal Z‐E isomerization completes after several days at room temperature. High stability of Z ‐form is explained by the restriction either the rotation around the nitrogen–nitrogen bond or the inversion process associated with thermal Z‐E isomerization.…”

Section: Introductionmentioning

confidence: 54%

Azobenzene‐containing LC polymethacrylates highly photosensitive in broad spectral range

Bobrovsky

Shibaev

Cigl

et al. 2016

J. Polym. Sci. Part A: Polym. Chem.

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Two photosensitive chiral liquid crystalline azobenzene‐containing polymethacrylates having different length of flexible spacer connecting chromophores with backbone were synthesized and their phase behavior and photo‐optical properties were studied. Both polymers consist of lateral methyl substituents in ortho‐position of azobenzene chromophores providing high photosensitivity even in red spectral region as well as high thermal stability of photoinduced Z‐form of azobenzene chromophores. It is shown, that smectic phase (SmA*) formation in films of polymer with longer spacer predetermines its quite unusual spectral response to UV and subsequent visible light actions. The SmA* phase promotes spontaneous homeotropic alignment of azobenzene chromophores in polymer films. UV‐irradiation induces not only E‐Z isomerization but also results in disruption of homeotropic alignment, whereas subsequent visible light action enables to obtain films with the low degree of chromophores orientation. The photo‐orientation phenomena under the action of polarized light of different wavelength on polymer films were studied. The possibility of using red polarized light of moderate intensity for optical photorecording on polymer films is demonstrated. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 2962–2970

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Section: Introductionmentioning

confidence: 54%

Azobenzene‐containing LC polymethacrylates highly photosensitive in broad spectral range

Bobrovsky

Shibaev

Cigl

et al. 2016

J. Polym. Sci. Part A: Polym. Chem.

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“…The spontaneous decay of the grating structure is of course not suitable for practical applications, but it is very convenient for research purposes, because the one and same sample can be used to perform different experiments. The decay of recorded patterns can be prevented by using photosensitive mesogens with very long lifetimes of the cis isomer, or by using the light-induced covalent attachment of mesogenic groups to the polymer backbone [31,32].…”

Section: Resultsmentioning

confidence: 99%

Mechanical Manipulation of Diffractive Properties of Optical Holographic Gratings from Liquid Crystalline Elastomers

Bošnjaković

Gregorc

et al. 2018

Applied Sciences

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An appealing property of optical diffractive structures from elastomeric materials is a possibility to regulate their optical patterns and consequently also their diffractive features with mechanical straining. We investigated the effect of strain on diffraction characteristics of holographic gratings recorded in a monodomain side-chain liquid crystalline elastomer. The strain was imposed either parallel or perpendicular to the initial alignment direction of the material. At temperatures far below the nematic-paranematic phase transition, straining along the initial alignment affects mainly the diffraction pattern, while the diffraction efficiency remains almost constant. In contrast, at temperatures close to the nematic-paranematic phase transition, the diffraction efficiency is also significantly affected. Straining in the direction perpendicular to the initial alignment strongly and diversely influences both the diffraction pattern and the diffraction efficiency. The difference between the two cases is attributed to shear-stripe domains, which form only during straining perpendicular to the initial alignment and cause optical diffraction that competes with the diffraction from the holographic grating structure.

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“…The synthesis of racemic material liquid crystal 2 is briefly presented in Scheme . The starting azophenol ( 1 ) was synthesized according to a previously reported procedure . Azophenol 1 was acylated by 4‐[(methoxycarbonyl)oxy]benzoyl chloride 2 in the presence of pyridine.…”

Section: Methodsmentioning

confidence: 99%

Influence of photoinduced isomerization on the chiral separation of novel liquid crystalline materials with a diazene moiety

Vojtylová

Cigl

Tomášková

et al. 2018

J of Separation Science

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The influence of photoinduced isomerization on the enantiomeric separation of two newly synthesized liquid crystalline materials, liquid crystals 1 and 2, was studied by high-performance liquid chromatography on a chiral stationary phase Chiralpack AD-3. Both materials have one chiral center and one diazene moiety. The compounds were separated into their E and Z isomeric forms. The conditions and time scale of the ultraviolet-induced E to Z transition were briefly evaluated. Under the optimized conditions, we were able to baseline separate the S and R enantiomers of both the studied materials in their E isomeric form. The chiral separation of liquid crystal 2 after ultraviolet irradiation was unsuccessful. In contrast, the chiral separation of liquid crystal 1 possessing a similar structure to liquid crystal 2 provided baseline separation in its Z isomeric form as well. Previously, we have shown the influence of photoinduced isomerization and its utilization in the enantioseparation on relatively simple molecules. Here, we demonstrate that (1) much more complex compounds can also be successfully separated despite the bulkiness of the achiral part of the structure and (2) photoinduced isomerization even for such complex molecules still strongly influences their chromatographic properties.

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Functional Photochromic Methylhydrosiloxane‐Based Side‐Chain Liquid‐Crystalline Polymers

Cited by 40 publications

References 50 publications

Azobenzene‐containing LC polymethacrylates highly photosensitive in broad spectral range

Azobenzene‐containing LC polymethacrylates highly photosensitive in broad spectral range

Mechanical Manipulation of Diffractive Properties of Optical Holographic Gratings from Liquid Crystalline Elastomers

Influence of photoinduced isomerization on the chiral separation of novel liquid crystalline materials with a diazene moiety

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