- Light-triggered syneresis of a water insoluble peptide-hydrogel effectively removes small molecule waste contaminants
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A short peptide based hydrogel exhibits aqueous insolubility, thixotropy and efficient light induced syneresis. Upon irradiation with UV light, the hydrogel shrinks and expells ~50% of the solvent. Syneresis is caused by light-triggered trans-cis isomerisation of an azobenzene moiety in the peptide derivative. This expulsion of solvent can be effectively exploited in the removal of low molecular weight contaminants in water.
- Chowdhuri, Sumit,Das, Basab Kanti,Das, Debapratim,Pramanik, Bapan,Scherman, Oren A.
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Read Online
- Optical and liquid crystalline properties of new alkyl-substituted azopolymers
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In the present work, we report the synthesis, the mesomorphic behavior and the laser-induced optical characteristics of side-chain liquid crystalline azopolymers without a spacer, but substituted with a hexyloxy group. The azopolymers were studied by DSC,
- Rodriguez-Gonzalez,Larios-Lopez,Navarro-Rodriguez,Solano,Martinez-Ponce
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p. 2831753 - 2911761
(2009)
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Read Online
- New para-substituted non-symmetric isoflavones for their fast photo-switching ability: Synthesis and their liquid crystal characterization
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The first example of non-symmetric isoflavone-based fast photo-switchable liquid crystals with different functional groups at the terminal position were synthesized and characterized. Polarizing optical microscopy study revealed that the compounds showed least ordered nematic phase. Optical photo switching study exhibited very fast photoisomerization effect in solution. The E-Z and Z-E conversion occurred around 3-5 s and 40-700 s respectively. This is also the first example of para-substituted non-symmetric isoflavone liquid crystals exhibiting very fast photo switching property in solution. Argument based on non-symmetrical behaviour might be the reason for the observed behaviour.
- Yuvaraj,Yam, Wan Sinn,Chan, Tze Nee,Goh, Yit Peng,Hegde, Gurumurthy
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p. 1115 - 1122
(2014/11/12)
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- Stabilization and optical switching of liquid crystal blue phase doped with azobenzene-based bent-shaped hydrogen-bonded assemblies
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We develop a new kind of bent-shaped hydrogen-bonded assemblies (H-bonded assemblies) to stabilize liquid crystal blue phases (LC-BPs) and optically switch the Bragg reflection band of BPs. Here the H-bonded assemblies are simply assembled with the proton
- Wang, Jiao,Shi, Yang,Yang, Kuan,Wei, Jie,Guo, Jinbao
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p. 67357 - 67364
(2015/08/24)
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- AZOBENZENE COMPOUND AND HEAT PUMP SYSTEM USING THE SAME
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PROBLEM TO BE SOLVED: To provide an azobenzene compound capable of repeated structural changes without heating, and a heat pump system using the same. SOLUTION: An azobenzene compound represented by the general formula (1) and undergoing cis-trans isomerization reaction upon light irradiation is used as a heat medium of a heat pump system. In the formula, at least one of R1 to R3 is (CH2CH2O)n-R10; R4 is R11, O-R11, NH-R11, or COO-R11; X- is Cl-, Br-, I-, BF4-, PF6-, CH3(CH2)nSO3-, TsO-, (YSO2)2 N-, or (NC)2 N-; n is an integer between 0 and 2; and Y is F, CF3, or C2F5. COPYRIGHT: (C)2015,JPO&INPIT
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Paragraph 0044; 0049; 0050
(2016/10/10)
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- Photoliquefiable ionic crystals: A phase crossover approach for photon energy storage materials with functional multiplicity
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Ionic crystals (ICs) of the azobenzene derivatives show photoinduced IC-ionic liquid (IL) phase transition (photoliquefaction) upon UV-irradiation, and the resulting cis-azobenzene ILs are reversibly photocrystallized by illumination with visible light. The photoliquefaction of ICs is accompanied by a significant increase in ionic conductivity at ambient temperature. The photoliquefaction also brings the azobenzene ICs further significance as photon energy storage materials. The cis-IL shows thermally induced crystallization to the trans-IC phase. This transition is accompanied by exothermic peaks with a total ΔH of 97.1 kJmol-1, which is almost double the conformational energy stored in cisazobenzene chromophores. Thus, the integration of photoresponsive ILs and self-assembly pushes the limit of solar thermal batteries.
- Ishiba, Keita,Morikawa, Masa-Aki,Chikara, Chie,Yamada, Teppei,Iwase, Katsunori,Kawakita, Mika,Kimizuka, Nobuo
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supporting information
p. 1532 - 1536
(2015/02/05)
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- AZOBENZENE COMPOUND AND HEAT PUMP SYSTEM USING IT
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PROBLEM TO BE SOLVED: To provide an azobenzene compound capable of changing a structure repeatedly without heating and a heat pump system using it. SOLUTION: An azobenzene compound expressed by the formula (1) and reacts by cis-trans isomerization by light radiation, is used as a heat medium of a heat pump system. The azobenzene compound expressed by the formula (1) is subjected to endotherm by melting latent heat when phase change from a solid phase trans body to a liquid phase cis body occurs, and is subjected to heat evolution when phase change from the liquid phase cis body to the solid phase trans body occurs. COPYRIGHT: (C)2015,JPO&INPIT
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Paragraph 0053; 0054
(2017/02/24)
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- Amphotropic azobenzene derivatives with oligooxyethylene and glycerol based polar groups
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A series of amphiphilic azobenzenes with one to three lipophilic alkyl chains at one end and polar groups with oligooxyethylene (EO) and racemic 3-glyceryl units at the opposite end was synthesized and their thermotropic and lyotropic liquid crystalline self-assemblies were studied by POM, DSC and XRD. Tilted and non-tilted lamellar phases with interdigitated double layer structures (SmCd and SmAd, respectively) were found for the compounds with a single alkyl chain, whereas hexagonal columnar phases were formed by the compounds with two or three alkyl chains. The effect of protic solvents, like formamide, ethylene glycol and water, was investigated for representative examples. For the compounds with the single chain, induction and stabilization of SmA phases were observed, though broad regions of lyotropic SmC phases were retained in most cases. Depending on the structure of the polar group, the hexagonal columnar phases were either removed or drastically stabilized by the solvents. Photoisomerisation of an azobenzene chromophore was also studied.
- Tan, Xiaoping,Zhang, Ruilin,Guo, Chunxiang,Cheng, Xiaohong,Gao, Hongfei,Liu, Feng,Bruckner, Johanna R.,Giesselmann, Frank,Prehm, Marko,Tschierske, Carsten
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p. 11202 - 11211
(2015/11/09)
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- Synthesis, mesomorphic and dielectric properties of 4-(cyanomethoxy)phenyl 4-alkoxybenzoates, 4-(cyanomethoxy)-4′-alkoxyazo- and -azoxybenzenes
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Preparation methods were developed for homologs of 4-(cyanomethoxy)phenyl 4-alkoxybenzoates (C7, C8, C9), 4-(cyanomethoxy)-4′-alkoxyazo (C2, C3, C 6), -azoxybenzenes (C3, C6) whose composition and structure were proved by elemental analysis and 1H NMR spectra. 4-(Cyanomethoxy) group destabilizes the mesophase, consequently, only four among the compounds obtained exhibit the thermotropic nematic mesomorphism.
- Kuvshinova,Burmistrov,Novikov,Litov,Aleksandriiskii,Koifman
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p. 615 - 620
(2014/07/08)
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- Side-Chain Liquid-Crystalline Polyoxetanes with a Spacer-Separated Azobenzene Moiety. II. Preparation and Characterization of Polyoxetanes Derived from 4-(4-Alkoxyphenylazo)phenyl 4-[7-(3-Methyl-3-oxetanyl)-1,6-dioxaheptyl]-benzoates
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A series of polyoxetanes were prepared by the cationic ring-opening polymerization of 4-(4-alkoxyphenylazo)phenyl 4-[7-(3-methyl-3-oxetanyl)-1,6-dioxaheptyl]benzoates using 0.08 molar amount of THF·BF3 in dichloromethane at 20 to 30° C. Although the product polymers indicated GPC-average molecular weights of around 9000 to 23000, in most cases, they did not have an unimodal molecular weight dispersity. The liquid-crystalline mesophases of the polymers were examined by differential scanning calorimetry and polarized optical microscopy; these textures were observed due to nematic and/or smectic mesophases over a wide temperature range from about 250° C to room temperature. The benzoate moiety, the longer p-substituted alkoxy tails, and the oxetane main chain play important roles in maintaining highly ordered, stable mesophases.
- Ogawa, Hiroshi,Hosomi, Tetsuya,Kosaka, Toshiaki,Kanoh, Shigeyoshi,Ueyama, Akihiko,Motoi, Masatoshi
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p. 175 - 187
(2007/10/03)
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- Mesogenic cyclopentadienyl cyclopalladated azobenzene complexes
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The novel coordinatively saturated cyclopentadienyl palladium complexes [PdLn(η5-C5H5)] (HLn = thermotropic 4-R,4′-R′-azobenzene; n = 1, R = R′ = C6H13; n = 2, R = R′ = C6/
- Ghedini, Mauro,Pucci, Daniela,Neve, Francesco
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p. 137 - 138
(2007/10/03)
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- Mesogenic 4-(2,3-Epoxypropoxy)-4'-alkoxyazoxybenzenes
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Optimal conditions for preparation of 4-(2,3-epoxypropoxy)-4'-alkoxyazoxybenzenes were developed, and 10 mesogenic homologs (n = 1-10) possessing an extended nematic mesophase were synthesized.Nonyloxy and decyloxy derivatives of epoxyazoxybenzene exhibit also smectic mesomorphism.
- Burmistrov, V. A.,Kuz'mina, S. A.,Koifman, O. I.
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p. 351 - 353
(2007/10/03)
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- Mesogenic properties of liquid crystals having a chiral semiflexible joint
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Two homologous series of mesogenic enantiomers with chiral semiflexible joint, -C*H(CH3)CH2COO-, are examined. High twist power and presence of blue phases with short lattice period are found for eleven examined compounds. Some effects of chirality in reentrant system are discussed. On phase diagram of enantiomers the SmAd phase area is shifted toward longer homologues as compared to racemates. In result, an island of the SmAd phase in the cholesteric sea exists on binary phase diagrams of R- and S- enantiomers. Triple divergence of the pitch in the cholesteric phase of a pure compound is observed.
- Gorecha,Pyzuk,Mieczkowski
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- Room-temperature Organometallic Chiral Liquid Crystals: Azoxymercury Complexes
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The new mercury complexes nCl> nH2n+1)-4'-azobenzene, n = 6,10> are liquid crystals which exhibit a chiral smectic C* mesophase at room temperature and clear at about 60 deg C.
- Omenat, Ana,Ghedini, Mauro
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p. 1309 - 1310
(2007/10/02)
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- ORIENTATION AND SPECTRAL CHARACTERISTICS OF THE AZOBENZENE CHROMOPHORE IN THE AMMONIUM BILAYER ASSEMBLY.
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Azobenzene-containing, single-chain ammonium amphiphiles in which the alkyl chain length in the tail and spacer portions was systematically varied were prepared, and their aggregation behavior in water was studied by electron microscopy, differential scanning calorimetry and absorption spectroscopy. These amphiphiles exist as molecular dispersions, hydrated microcrystals, micelles, or bilayers. The formation of stable bilayers was deduced on the basis of three criteria which include the spectral agreement between aqueous dispersions and the corresponding cast films. Stable bilayers were obtainable when the sum of tail and spacer is not smaller than C//1//4 to C//1//6, and the tail is at least C//8.
- Shimomura,Ando,Kunitake
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p. 1134 - 1143
(2007/10/02)
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