Journal articles: 'Mesophase'

1

Paquette, Joseph A., Katie M. Psutka, Colin J. Yardley, and Kenneth E. Maly. "Probing the structural features that influence the mesomorphic properties of substituted dibenz[a,c]anthracenes." Canadian Journal of Chemistry 95, no. 4 (April 2017): 399–409. http://dx.doi.org/10.1139/cjc-2016-0505.

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We report the synthesis and mesophase characterization of a series of novel hexaalkoxydibenzanthracenes to probe the effect of side-chain length variation and substituents on the mesophase temperature range. A series of hexaalkoxydibenz[a,c]anthracenes (2a–2i) with varying chain lengths were prepared by Suzuki coupling of the appropriate boronate ester with the corresponding dialkoxydibromonaphthalenes, followed by oxidative cyclization. Compounds 2a–2i were also brominated in the 10 and 13 positions to yield the corresponding dibromo series, 4a–4i. While none of the compounds, 2a–2i, exhibited columnar mesophases, all of the compounds in series 4a–4i did exhibit columnar phases over broad temperature ranges. To further investigate the effect of substituents on the mesomorphic properties of hexaalkoxydibenzanthracenes, we also prepared iodo-substituted 8, nitro-substituted 9, and amino-substituted 10. A comparison of the mesophase temperature range with previously reported compounds 3–7 shows that electron-withdrawing groups promote the formation of stable mesophases. However, our results also suggest that the substituents affect mesophase stability by participating in intermolecular contacts within the columnar stacks of the mesophase.

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Mukai, Hidetomo, Miho Yokokawa, Masahiro Ichihara, Kazuaki Hatsusaka, and Kazuchika Ohta. "Discotic liquid crystals of transition metal complexes 42: the detailed phase structures and phase transition mechanisms of two Cub mesophases shown by discotic liquid crystals based on phthalocyanine metal complexes." Journal of Porphyrins and Phthalocyanines 14, no. 02 (February 2010): 188–97. http://dx.doi.org/10.1142/s1088424610001908.

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We found in our previous works that the sandwich-type phthalocyanine-based rare earth metal complexes, bis[2,3,9,10,16,17,23,24-octakis(3,4-dialkoxyphenoxy)phthalocyaninato]lanthanoid(III) ({[( C n O )2 PhO ]8 Pc }2 M, M = Eu and Lu , n = 8–16) (1 and 3), exhibited two thermotropic cubic mesophases, Cub1 and Cub2, together with columnar mesophases. It is rare that the discotic liquid crystalline compounds show the cubic mesophase. We revealed that their symmetries of the lower temperature Cub1 mesophase and the higher temperature Cub2 mesophase were [Formula: see text] and [Formula: see text], respectively. However, their detailed phase structures were not revealed in the previous works. In this work, we have synthesized a series of novel sandwich-type phthalocyanine-based terbium complexes, bis[2,3,9,10,16,17,23,24-octakis(3,4-dialkoxyphenoxy)phthalocyaninato]terbium(III) ({[( C n O )2 PhO ]8 Pc }2 Tb , n = 8–16) (2). Their mesomorphic properties have been investigated using polarization microscope, DSC and temperature-dependent X-ray diffraction techniques. As the result, the present Tb complexes (2) also showed two cubic mesophases, [Formula: see text] and [Formula: see text], together with columnar mesophases, as well as the previous Eu homologs (1) and Lu homologs (3). We have furthermore investigated by using temperature-dependent electronic absorption spectroscopy to reveal their detailed phase structures and phase transition mechanism of these two Cub mesophases. We have revealed that the [Formula: see text] mesophase forms a bicontinuous structure consisting of branched columns like jungle gym, but that the [Formula: see text] mesophase forms a discontinuous structure consisting of short columns like drums that resulted from the cutting off of the branched columns.

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Godbert, Nicolas, Alessandra Crispini, Mauro Ghedini, Manuela Carini, Francesco Chiaravalloti, and Andrea Ferrise. "LCDiXRay: a user-friendly program for powder diffraction indexing of columnar liquid crystals." Journal of Applied Crystallography 47, no. 2 (March 19, 2014): 668–79. http://dx.doi.org/10.1107/s1600576714003240.

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The formulation of a standard computerized procedure for the indexing of powder X-ray diffraction (PXRD) patterns of columnar liquid crystals, with the determination of all structural information extracted from a properly indexed PXRD spectrum and the attribution of the columnar mesophase symmetry, is presented. In particular, the proposed program notably accelerates the identification of columnar mesophases together with thein situdetermination of their structural parameters such as mesophase type, space group, cell parameters, cross-section area, intermolecular stacking distance between consecutive discoids and, in the case of ordered mesophases, the estimation of the number of molecules constituting each discoid.

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Tian, Mei, Lu Lu Guo, Dan Shu Yao, Jian She Hu, Xiao Zhi He, and Hong Guang Wang. "Influence of Chiral Maltose on the Mesomorphic Properties of Main-Chain Liquid-Crystalline Polymers." Advanced Materials Research 535-537 (June 2012): 1218–21. http://dx.doi.org/10.4028/www.scientific.net/amr.535-537.1218.

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A series of main-chain liquid-crystalline polymers containing maltose were synthesized by interfacial condensation reactions of sebacyl chloride, 4,4’-Dihydroxy-2,2’-dimethyl Benzalazine(DDBA), and 1-O-[4´-O-(α-D-glucopyranosyl)-ß-D-glucopyranosyl]-methanol(MM). The effects of MM on characteristics of liquid-crystalline properties were studied. P1- P3 exhibited nematic mesophase on heating and cooling cycle, while P4- P7 exhibited both chiral smectic A and nematic mesophases on heating cycle and nematic mesophase on cooling cycle. P8 did not exhibit any mesophase on heating and cooling cycle. The glass-transition temperature decreased with increasing concentration of MM.

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5

Kohne, Bernd, Klaus Praefcke, and Jan Billard. "Uber die drei discotischen Mesophasen der scyllo-Inosithexaester / On the Three Discotic Mesophases of scyllo-Inositol Hexaesters." Zeitschrift für Naturforschung B 41, no. 8 (August 1, 1986): 1036–44. http://dx.doi.org/10.1515/znb-1986-0819.

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AbstractThe mesophases of eleven homologous hexaesters ( 1b -1) of the naturally occurring scylloinositol (1a ) representing the first series of alicyclic saturated discogens are studied by calorimetry and optical microscopy. The three derivatives 1 b -d of this hexahydroxy cyclohexane with each six acetyl, propionyl or butyroyl side chains, respectively, exhibit a very organized discophase D1. The hexa-0-acetyl-scyllo-inositol (1b , range of mesophase: Δt = 4.8 °C!) is the discogen having the shortest identical ester groups as lateral functions so far reported for discotic liquid crystals. The pentanoyloxy com pound (1e) exhibits a monotopic D0 mesophase and an enantiotropic optically isotropic and, probably, cubic mesophase D0 different from the smectic D mesophase. Versus increasing temperature the phase sequences are D1 → DE and D1 → D0. Examples of mutual orientation of D1 and DE discophases and binary mixtures exhibiting stable DE discophase at room temperature are also reported. The mesophases of seven more compounds (1f-1) of the homologous series having lateral functions larger than pentanoyloxy are identified by total miscibility as discophase DE. Their stable temperature ranges are very wide e.g. hexa-0-heptanoyl-scyllo- inositol (1g , Δt = 132 °C) which are exceeded only by those discogens having much larger “cores” (up to now of aromatic character only).

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6

Pirondini, Laura, Gabriele Vecchi, Sara Negri, Alfredo Di Blasi, Chiara Massera, and Enrico Dalcanale. "Design and Preparation of Mesogenic Cavitands." Collection of Czechoslovak Chemical Communications 69, no. 6 (2004): 1362–80. http://dx.doi.org/10.1135/cccc20041362.

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Mesogenic cavitands have been prepared for the first time. They form uniaxial disordered columnar mesophases (Dhd). The structure requirements for mesophase formation have been identified: (i) macrocyclic cores with thickness below 5 Å and (ii) four large (3,4,5-tris{[4-(dodecyloxy)benzyl]oxy}benzoyl)oxy groups at the upper rim. The orientation of the molecules within the columns is random, excluding the formation of intracolumnar cavities of molecular dimensions in the mesophase.

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7

Pini, Davide. "Some general features of mesophase formation in hard-core plus tail potentials." Soft Matter 14, no. 31 (2018): 6595–612. http://dx.doi.org/10.1039/c8sm01124a.

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8

Ichihara, Masahiro, Ayumi Suzuki, Kazuaki Hatsusaka, and Kazuchika Ohta. "Discotic liquid crystals of transition metal complexes 38†: peripheral chain substituent position effect on columnar mesophase and stacking structures of novel phthalocyanine-based liquid crystals." Journal of Porphyrins and Phthalocyanines 11, no. 07 (July 2007): 503–12. http://dx.doi.org/10.1142/s1088424607000588.

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In order to clarify the peripheral chain substitution position effect on columnar mesophase and stacking structures, we have synthesized three novel series of discotic liquid crystals (1-3) having octakis(phenoxy)phthalocyaninato copper(II) as a central core and one peripheral chain at the para position (1), meta position (2) or ortho position (3) of each phenoxy group, and three more novel series of discotic liquid crystals (4-6) having the same central core and two peripheral chains at para and meta positions (4), meta and meta positions (5) or ortho and meta positions (6) of each phenoxy group. Their columnar mesophase and stacking structures were investigated with a polarizing optical microscope, a differential scanning calorimeter and a temperature-dependent X-ray diffractometer. According to the results, their columnar mesophase and stacking structures strongly depended on the peripheral chain substitution positions and the number of peripheral chains. Derivatives 3 and 5 are viscous isotropic liquid at room temperature. Derivatives 1, 2, 4 and 6 exhibit various kinds of columnar mesophases: 1 Colhd; 2 Colhd and Colho; 4 Colhd, Colrd(P21/a), Coltet.d and Cub ( Pn [ three bar ] m ); 6 Colhd, Colrd(P21/a) and Colrd(X). Moreover, derivatives 1, 4 and 6 exhibit disordered columnar mesophases. However, derivative 2 only exhibits an ordered columnar mesophase and its X-ray diffraction pattern shows a sharp reflection corresponding to a very short intracolumnar stacking distance of 3.33 Å. Thus, we can drastically change the mesophase and stacking structures by the peripheral chain substitution positions and the number of peripheral chains at each phenoxy group. This is a new way of controlling mesomorphic structure.

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9

Zimmermann, H., R. Poupko, Z. Luz, and J. Billard. "Temperature Dependent Sign Reversal of the Optical Anisotropy in Pyramidic Mesophases." Zeitschrift für Naturforschung A 41, no. 9 (September 1, 1986): 1137–40. http://dx.doi.org/10.1515/zna-1986-0908.

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Hexasubstituted tribenzocyclononene derivatives with R = -OC(O)C6H4CnH2n+i and R = -OC(O)C6H4OCnH2n+1 possess enantiotropic pyramidic mesophases. These mesophases exhibit an uncommon feature in that their optical anisotropy changes sign as function of temperature within the mesophase region. It is suggested that this effect reflects conformational changes involving the side chain benzene ring.

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10

Tang, Xin De, Long Cheng Gao, and Nian Feng Han. "Influence of the Terminal Substituent of Azobenzene on the Liquid Crystalline Property of ABA Triblock Copolymers." Key Engineering Materials 428-429 (January 2010): 122–25. http://dx.doi.org/10.4028/www.scientific.net/kem.428-429.122.

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The influence of the terminal substituent of azobenzene on the liquid crystalline property of ABA triblock copolymers was studied. Three kinds of azobenzene-containing monomers with different terminal substituents were respectively used to synthesize ABA triblock copolymers (denoted as PMMAzo12-PEG13-PMMAzo12, PEMAzo14-PEG13-PEMAzo14, and PNMAzo14-PEG13-PNMAzo14) by atom transfer radical polymerization (ATRP). These copolymers were characterized with 1H NMR and GPC, and exhibited controlled molecular weights and narrow molecular weight distributions. Differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) have shown that these copolymers have mesophases. PMMAzo12-PEG13-PMMAzo12 has a smectic mesophase and a nematic mesophase, while both PEMAzo14-PEG13-PEMAzo14 and PNMAzo14-PEG13-PNMAzo14 have a nematic mesophase. This demonstrates that the LC properties of these copolymers highly depend on the terminal substituent of azobenzene.

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11

Harkness, Brian R., and Derek G. Gray. "Left- and right-handed chiral nematic mesophase of (trityl)(alkyl)cellulose derivatives." Canadian Journal of Chemistry 68, no. 7 (July 1, 1990): 1135–39. http://dx.doi.org/10.1139/v90-175.

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A series of novel specifically substituted 6-O-trityl-2,3-O-alkyl cellulose derivatives have been prepared by the reaction of triphenylmethyl (trityl) cellulose in DMSO with powdered sodium hydroxide and an alkyl iodide (iodohexane, iodopentane, and iodobutane). These derivatives form lyotropic chiral nematic mesophases that exhibit both left- and right-handed twists. The dilute solution circular dichroism due to the phenyl chromophores along the chain does not correlate with the twist sense of the tertiary structures. However, a striking difference in the optical activity of the phenyl chromophores was observed in mesophases with the opposite twist sense. This may reflect some molecular factor responsible for the change in the macroscopic twist sense, or it may be due to the chirality of the helicoidal tertiary structure of the mesophase. Keywords: cellulose, trityl, mesophase, cholesteric, chiroptical.

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12

Reddy, M. Guruprasad, Nitin P. Lobo, Arun Roy, K. V. Ramanathan, and T. Narasimhaswamy. "Strikingly different molecular organization and molecular order of tetracatenar mesogens in columnar mesophases revealed by XRD and 13C NMR." Physical Chemistry Chemical Physics 22, no. 41 (2020): 23986–97. http://dx.doi.org/10.1039/d0cp03933k.

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XRD and ¹³C NMR investigations of four tetracatenar mesogens reveal lamellar mesophase for a lower homologs and centre rectangular/2D hexagonal columnar mesophases for higher homologs with strikingly different molecular orientations.

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13

Mendozza, Marco, Arianna Balestri, Costanza Montis, and Debora Berti. "Controlling the Kinetics of an Enzymatic Reaction through Enzyme or Substrate Confinement into Lipid Mesophases with Tunable Structural Parameters." International Journal of Molecular Sciences 21, no. 14 (July 20, 2020): 5116. http://dx.doi.org/10.3390/ijms21145116.

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Lipid liquid crystalline mesophases, resulting from the self-assembly of polymorphic lipids in water, have been widely explored as biocompatible drug delivery systems. In this respect, non-lamellar structures are particularly attractive: they are characterized by complex 3D architectures, with the coexistence of hydrophobic and hydrophilic regions that can conveniently host drugs of different polarities. The fine tunability of the structural parameters is nontrivial, but of paramount relevance, in order to control the diffusive properties of encapsulated active principles and, ultimately, their pharmacokinetics and release. In this work, we investigate the reaction kinetics of p-nitrophenyl phosphate conversion into p-nitrophenol, catalysed by the enzyme Alkaline Phosphatase, upon alternative confinement of the substrate and of the enzyme into liquid crystalline mesophases of phytantriol/H2O containing variable amounts of an additive, sucrose stearate, able to swell the mesophase. A structural investigation through Small-Angle X-ray Scattering, revealed the possibility to finely control the structure/size of the mesophases with the amount of the included additive. A UV–vis spectroscopy study highlighted that the enzymatic reaction kinetics could be controlled by tuning the structural parameters of the mesophase, opening new perspectives for the exploitation of non-lamellar mesophases for confinement and controlled release of therapeutics.

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14

Marković, J. M., N. P. Trišović, T. Tóth-Katona, M. K. Milčić, A. D. Marinković, C. Zhang, A. J. Jákli, and K. Fodor-Csorba. "A structure–property relationship study of bent-core mesogens with pyridine as the central unit." New J. Chem. 38, no. 4 (2014): 1751–60. http://dx.doi.org/10.1039/c3nj01430d.

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The synthesis and characterization of pyridine bent-core liquid crystals are reported. Some compounds exhibit B1 and B7 mesophases. Lower and wider mesophase ranges are obtained by decreasing the polarity of linkers between the pyridine ring and the inner aromatic rings, and increasing the length of terminal chains.

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NESRULLAJEV, ARIF, BELKIZ BILGIN ERAN, and ÇIDEM YÖRÜR. "4-(OCTYLOXY)-N-(4-HEXYLPHENYL)-2-HYDROXYBENZALIMINE THERMOTROPIC COMPOUND: MORPHOLOGIC, MESOMORPHIC, THERMOTROPIC, THERMOOPTICAL AND THERMODYNAMICAL PROPERTIES." International Journal of Modern Physics B 22, no. 03 (January 30, 2008): 281–91. http://dx.doi.org/10.1142/s0217979208038582.

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In this work, the mesomorphic, morphologic, thermotropic, thermooptical, and thermodynamical properties of 4-(octyloxy)-N-(4-hexylphenyl)-2-hydroxybenzalimine thermotropic liquid crystalline compound, which was synthesized by our group, have been studied in detail. This compound displays smectic C and nematic mesophases. These mesophases are enantiotropic and exhibit specific confocal and schlieren textures, respectively. Thermotropic, thermooptical, and thermodynamical properties of the compound at direct and reverse phase transitions between smectic C and nematic mesophases and also between nematic mesophase and isotropic liquid have been investigated. The peculiarities of the bistable heterophase regions of these phase transitions have been studied.

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Mukai, Hidetomo, Kazuaki Hatsusaka, and Kazuchika Ohta. "Discotic liquid crystals of transition metal complexes 39: columnar mesomorphism and homeotropic alignment speed of sandwich-type of double-deckers and triple-deckers based on phthalocyaninato lutetium metal complexes." Journal of Porphyrins and Phthalocyanines 11, no. 12 (December 2007): 846–56. http://dx.doi.org/10.1142/s1088424607000977.

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A series of sandwich-type metal complexes, bis[2,3,9,10,16,17,23,24-octakis(3,4-dialkoxyphenoxy)phthalocyaninato]lutetium(III) ({[( C n O )2 PhO ]8 Pc }2 Lu (n = 8−16): double-deckers (2)), were synthesized. As the by-product, tris[2,3,9,10,16,17,23,24-octakis(3,4-diakoxyphenoxy)phthalocyaninato]dilutetium(III) ({[( C n O )2 PhO ]8 Pc }3 Lu 2 (n = 8, 9, 11, 12, 14, 16): triple-deckers (3)) were successfully separated. The mesomorphic properties of these double-deckers (2) and triple-deckers (3) were investigated using a polarization microscope, differential scanning calorimetry and temperature-dependent X-ray diffraction techniques. The double-deckers (2) showed Colh , Cub and Coltet mesophases for n ≥ 10. On the other hand, the triple-deckers (3) showed only a Colr mesophase for n = 8, only a Coltet mesophase for n = 14, and both Colr and Coltet mesophases for n = 9, 11, 12 and 16. For the Coltet mesophase, both the double-deckers (2) and the triple-deckers (3) exhibited spontaneous homeotropic alignment in a large area. In comparison with the homeotropic alignment of these present lutetium complexes 2, 3 and the previous copper complexes, 2,3,9,10,16,17,23,24-octakis(3,4-dialkoxyphenoxy)phthalocyaninato copper(II) ([( C n O )2 PhO ]8 PcCu (n = 9-14): single-decker (1)), the alignment was fast, slow and fast, respectively, in the order of the single-deckers (1), double-deckers (2) and triple-deckers (3). Very interestingly, the complexes 1 and 3 which have flat Pc macrocycles gave fast alignment, whereas the complexes, 2, which have non-flat Pc macrocycles, gave slow alignment. Thus, it was revealed for the first time that the flatness of discotic liquid crystalline molecules influences the speed of homeotropic alignment.

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Speziale, Chiara, Livia Salvati Manni, Cristina Manatschal, Ehud M. Landau, and Raffaele Mezzenga. "A macroscopic H+and Cl−ions pump via reconstitution of EcClC membrane proteins in lipidic cubic mesophases." Proceedings of the National Academy of Sciences 113, no. 27 (June 16, 2016): 7491–96. http://dx.doi.org/10.1073/pnas.1603965113.

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Functional reconstitution of membrane proteins within lipid bilayers is crucial for understanding their biological function in living cells. While this strategy has been extensively used with liposomes, reconstitution of membrane proteins in lipidic cubic mesophases presents significant challenges related to the structural complexity of the lipid bilayer, organized on saddle-like minimal surfaces. Although reconstitution of membrane proteins in lipidic cubic mesophases plays a prominent role in membrane protein crystallization, nanotechnology, controlled drug delivery, and pathology of diseased cells, little is known about the molecular mechanism of protein reconstitution and about how transport properties of the doped mesophase mirror the original molecular gating features of the reconstituted membrane proteins. In this work we design a general strategy to demonstrate correct functional reconstitution of active and selective membrane protein transporters in lipidic mesophases, exemplified by the bacterial ClC exchanger fromEscherichia coli(EcClC) as a model ion transporter. We show that its correct reconstitution in the lipidic matrix can be used to generate macroscopic proton and chloride pumps capable of selectively transporting charges over the length scale of centimeters. By further exploiting the coupled chloride/proton exchange of this membrane protein and by combining parallel or antiparallel chloride and proton gradients, we show that the doped mesophase can operate as a charge separation device relying only on the reconstituted EcClC protein and an external bias potential. These results may thus also pave the way to possible applications in supercapacitors, ion batteries, and molecular pumps.

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18

Zakaria, Mohamed A., Mohammed Alazmi, Kanubhai D. Katariya, Yeldez El Kilany, El Sayed H. El Ashry, Mariusz Jaremko, Mohamed Hagar, and Sayed Z. Mohammady. "Mesomorphic Behaviour and DFT Insight of Arylidene Schiff Base Liquid Crystals and Their Pyridine Impact Investigation." Crystals 11, no. 8 (August 18, 2021): 978. http://dx.doi.org/10.3390/cryst11080978.

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A new series of Schiff base liquid crystal have been prepared and studied. Schiff bases of p-alkyl aniline derivatives and 4-phenyl pyridine-4′-carbaldehyde were prepared. The terminal alkyl groups substituting aniline are of varied chain length, namely C8, C12 and C14. The structures of the compounds were elucidated by 1H NMR and 13C NMR. The mesomorphic thermal and optical characteristics of the samples were determined via differential thermal analysis (DSC) and polarization optical microscopy (POM). All compounds exhibit enantiotropic dimorphic mesophase behaviour, referred to as smectic X1 (SmX1) and smectic X2 (Sm A). Experimental results obtained for the mesophases were correlated with density functional theory (DFT) theoretical calculations. The results of the new series are further compared to two series of compounds bearing pyridine (two ring Schiff bases) and biphenyl, respectively, in their mesogens. The series of compounds of one pyridine ring are generally not mesomorphic. The results indicate that the alkyl chain length has a strong impact on the mesomorphic characteristics and thermal stabilities of the different mesophases. As a trend, the temperature ranges of both of smectic mesophases of all compounds are higher in new compounds bearing the 4-phenyl pyridine moiety. In addition, the total mesophase range is generally higher in the new compounds when compared to their biphenyl analogues. Finally, theoretical DFT calculations were performed to illustrate the experimental finding of the mesomorphic behaviour in terms of the molecular geometry and aromaticity, π–π stacking and LOL-π.

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Han, Xian Gen, Xu Zhong Chen, Lu Lu Qian, and Xian Yong We. "Hydrogen Bonded Side Chain Liquid Crystallines Based on Poly(4-Vinylpridine)." Advanced Materials Research 239-242 (May 2011): 455–58. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.455.

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A series of novel liquid crystal were synthesized with alkyloxyben- zimidoylbenzoic acid (CnABOH) and poly(4-binylpridind) (PVP) through hydrogen bond self-assemble between carboxyl groups of alkyloxybenzimidoylbenzoic and nitrogen of PVP. PVP was used as a hydrogen bond acceptor polymer. The CnABOH (n is the number of carbon atom) had been used as H-bond donor. The existence of H-bond was confirmed used FTIR spectroscopy. Optical microscopy was used to investigate liquid crystalline behaviors. The mesophases of the complexes (PVP-CnABOH) were obviously different from LC behaviors of the CnABOH. With increasing length of terminal group, the melting temperature reduced and the temperature range of the LC mesophase increased. For instance, while the number of carbon atom increased from 3 to 8, the melting temperature reduced from 180°C to 156°C and the range of LC mesophase increased from 36°C to 84°C.

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20

Koßmehl, Gerhard, and Frank Dirk Hoppe. "Liquid Crystalline Compounds in the Thiophene Series, Part 7+." Zeitschrift für Naturforschung B 48, no. 12 (December 1, 1993): 1807–20. http://dx.doi.org/10.1515/znb-1993-1218.

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Compounds with two mesogenic groups without terminal alkyl chains or other groups containing thiophene systems have been prepared from α.ω-bis(5-formyl-2-thienyl)alkanes (series 1) and various phosphonium salts by Wittig-reaction. The chemical structures of the new compounds have been characterized by their elemental analyses, IR and 1H NMR spectra and MS. The liquid crystalline properties of these compounds were characterized by differential scanning calorimetry (DSC) and polarizing microscopy. Mesogenic cores with one thiophene system and two benzene systems give rise to liquid crystalline phases. These compounds with one vinylene group in each core (series 2 and 3) are mostly monotropic, those with two or three vinylene groups are enantiotropic liquid crystalline. Exchanging one vinylene group by a azomethine group in each core reduces the temperature range of the mesophase or destroys the liquid crystallinity completely. In contrast to E,E-1-(5-butyl-2-thienylvinyl)-4-(styryl)benzene (9) with no mesophase the corresponding all-E-α.ω-bis{5-[4-(4-styryl)styryl]-2-thienyl}alkanes (series 5) show over a wide temperature range with increasing inner chain length more and more high ordered mesophases. all-E-α.ω-Bis{5-[4-(4-phenylbuta-1.3-dienyl)styryl]-2-thienyl}alkanes (series 7) decompose in their mesophases.

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Gradišek, Anton, Mario Cifelli, Michal Wojcik, Tomaž Apih, Sergey Dvinskikh, Ewa Gorecka, and Valentina Domenici. "Study of Liquid Crystals Showing Two Isotropic Phases by 1H NMR Diffusometry and 1H NMR Relaxometry." Crystals 9, no. 3 (March 26, 2019): 178. http://dx.doi.org/10.3390/cryst9030178.

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In this work, we report a study of two thermotropic liquid crystalline samples showing a not common mesophase behavior. The samples, namely a di-benzyloxy biphenyl derivative labelled 9/2 RS/RS, and a bimesogenic liquid crystal labelled L1, show a direct transition between two isotropic phases followed, at lower temperatures, by the optically isotropic, 3D structured, cubic phase. These systems have been investigated by means of 1H NMR diffusometry and 1H NMR relaxometry in order to characterize their isotropic–isotropic’–cubic mesophase behavior, mainly on the dynamic point of view. In particular, the temperature trend of the self-diffusion coefficients measured for both samples allowed us to significantly distinguish between the two isotropic phases, while the temperature dependence of the 1H spin-lattice relaxation time (T1) did not show significant discontinuities at the isotropic–isotropic’ phase transition. A preliminary analysis of the frequency-dependence of 1H T1 at different temperatures gives information about the main motional processes active in the isotropic mesophases.

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Lee, Young Seak, and Soo Jin Park. "Influence of Multiwalled Carbon Nanotube on Rheological Behavior of Mesophase Pitches." Solid State Phenomena 135 (February 2008): 47–52. http://dx.doi.org/10.4028/www.scientific.net/ssp.135.47.

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The rheological behaviors of mesophase pitch containing different contents (0, 1.0, 2.0 wt%) of multi-wall carbon nanotubes (MWNTs) were studied by using ARES cone-plate rheometer. The dynamic response of mesophase pitch containing MWNTs was different from that of pure mesophase pitch due to the MWNTs as a suspension in viscous pitch. The dynamic viscosity increased with increasing the amount of MWNTs, which is a clear evidence of the interruption of MWNTs in mesophase pitch. Also, the phase angle result indicates that mesophase pitch containing MWNT had less elastic nature than pure mesophase pitch.

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Zhang, Wen Wen, Xiu Jun Liu, Tong Qi Li, and Zhen Fan. "Size Distributions of Mesophase Microbeads Obtained from Heterogeneous and Homogeneous Systems." Key Engineering Materials 609-610 (April 2014): 571–76. http://dx.doi.org/10.4028/www.scientific.net/kem.609-610.571.

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Mesophase microbeads were prepared by thermal condensation in the presence of heterogeneous and homogeneous systems. Morphologies and sizes of mesophase microbeads are characterized by scanning electronic microcopy (SEM), polarized light optical microphotography (PLOM) and laser particle size analyzer. SEM and PLOM results exhibit that mesophase microbeads have a narrow size distribution and many large particle in heterogeneous system. In homogeneous system, there are a great deal of smaller mesophase microbeads and a very little of larger mesophase microbeads. The laser particle size analysis results show that size distribution of mesophase microbeads in heterogeneous system is quite different from that in homogeneous system. There are multi-peaks on volume distribution curve in heterogeneous system. Larger mesophase microbeads are mainly in tens micron peak of size distribution curve. In homogeneous system, particle size of mesophase microbeads has a wide distribution and only single peak on size distribution curve. Moreover, sulfur concentration in reaction system makes the size of mesophase microbeads increase and the size distribution curve move to larger particle diameter. But sulfur concentration can not affect the curve pattern of size distribution.

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24

Honda, Hidemasa. "CARBONACEOUS MESOPHASE." TANSO 1986, no. 126 (1986): 120–38. http://dx.doi.org/10.7209/tanso.1986.120.

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25

Bhyrappa, Puttaiah, Chellaiah Arunkumar, Babu Varghese, Doddamane S. Shankar Rao, and Subbarao K. Prasad. "Synthesis and mesogenic properties of β-tetrabrominated tetraalkyloxyporphyrins." Journal of Porphyrins and Phthalocyanines 12, no. 01 (January 2008): 54–64. http://dx.doi.org/10.1142/s108842460800008x.

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A new class of 2,3,7,8-tetrabromo-5,10,15,20-tetrakis(4'-n-1-alkyloxyphenyl)porphyrins, H 2 T (4'- OC n P ) PBr 4 (n = 4,6,8,10,12,14,16 and 18) and their Cu(II) complexes have been synthesized regioselectively and their mesophase properties explored. The mesogenic properties of the porphyrins were examined by differential scanning calorimetry and optical microscopy. An increase in alkyl chain length of the mesogens, showed an increase in melting point temperature and lowering of their clearing point temperatures with the narrower mesophases. This has been ascribed to the decreased π-π interactions as evidenced from the crystal structure of H 2 T (4'- OC 6 P ) PBr 4· THF derivative. MT (4'- OC n P ) PBr 4 derivatives showed rectangular mesophases in contrast to discotic lamellar mesophases reported for the planar MT (4'- OC n P ) P mesogens.

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26

Sato, Hiroyuki, Kensaku Igarashi, Yoshitaka Yama, Masahiro Ichihara, Eiji Itoh, and Kazuchika Ohta. "Discotic liquid crystals of transition metal complexes 45: parity effect of the number of d-electrons on stacking distances in the columnar mesophases of octakis-(m-alkoxyphenoxy)phthalocyaninato metal(II) complexes." Journal of Porphyrins and Phthalocyanines 16, no. 10 (October 2012): 1148–58. http://dx.doi.org/10.1142/s1088424612501131.

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We have synthesized 34 novel homologous discotic liquid crystals, octakis(m-alkoxyphenoxy)phthalocyaninato metal(II) {abbreviated as (m- CnOPhO)8PcM (M = Co(1), Ni(2), Cu(3), Zn(4) and H2 (5); n = 8(a), 10(b), 12(c), 14(d), 16(e), 18(f) and 20(g))}, and investigated parity effect of the number of d-electrons on the stacking distances in their columnar mesophases. It was revealed from temperature-dependent wide angle X-ray diffraction studies that each of the cobalt(II) (d7) complexes (1a–1g) and the copper(II) (d9) complexes (3b–3g) showed a single hexagonal ordered columnar (Colho) mesophase with a very short stacking distance at 3.3 Å, and that the nickel(II) (d8) complexes (2a–2g) and the metal-free (d0) derivatives (5a–5g) showed a single pseudo-hexagonal ordered columnar (Colrho) mesophase with a little bit longer stacking distances at 3.4 Å. Very interestingly, the nickel complex (2a) and metal-free derivatives (5a–5c) gave an extremely big (001) reflection peak with the second (002) reflection peak. Furthermore, the zinc(II) (d10) complexes (4a–4g) showed two different rectangular ordered columnar mesophases, Colro(P2/m) and Colro(P21/a), with a little bit longer stacking distance at 3.4 Å. Thus, the shorter stacking distance, 3.3 Å, appeared for the odd number of d-electrons, whereas the longer stacking distance, 3.4 Å, appeared for the even number of d-electrons. Hence, the stacking distances depend on parity of the number of d-electrons in the central metal(II). To our best knowledge, it is the first example of parity effect on the stacking distances in columnar mesophases.

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27

Yue, Li, Xue Fei Zhao, Shi Quan Lai, Xiao Xia Li, Liang Liang Gao, Ke Hou, and Han Shi Wang. "Kinetics of Mesophase Sphere Formation of Toluene Soluble Fraction." Advanced Materials Research 750-752 (August 2013): 1855–59. http://dx.doi.org/10.4028/www.scientific.net/amr.750-752.1855.

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The toluene soluble (TS) fraction prepared from a middle-temperature coal tar pitch was subjected to a series of thermal treatments at the various temperatures from 410 °C to 470 °C for different periods of time. The samples obtained after heat treatment was quenched to ambient temperature. Mesophase spheres were separated from the quenched samples using washing oil and quinoline. The kinetics of mesophase sphere formation of the TS fraction was studied, based on the data derived from the time-dependent changes in the mesophase sphere content. It was clarified that the mesophase sphere formation of TS fraction was an autocatalytic type reaction. The rate law and the rate constants for the mesophase sphere formation at holding temperatures of 410°C, 430°C, 450°C and 470°C were determined. The rate constants of the mesophase sphere formation follow the Arrhenius equation. The Arrhenius parameters of the mesophase sphere formation are 200.2 kJ mol-1 of the activation energy and 2.71x1012 % -1 h-1 of the pre-exponential factor. The treatment temperature had a greater effect on the formation of mesophase spheres than the treatment time.

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28

Al-Mutabagani, Laila A., Latifah Abdullah Alshabanah, Hoda A. Ahmed, Khulood A. Abu Al-Ola, and Mohamed Hagar. "New Rod-Like H-Bonded Assembly Systems: Mesomorphic and Geometrical Aspects." Crystals 10, no. 9 (September 8, 2020): 795. http://dx.doi.org/10.3390/cryst10090795.

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Experimental and geometrical approaches of new systems of mesomorphic 1:1 supramolecular H-bonded complexes (SMHBCs) of five rings are discussed. The H-bonding between 4-alkoxyphenylimino benzoic acids (An, as proton acceptor) and 4-(4′–pyridylazophenyl) 4′′-alkoxybenzoates (Bm, as proton donor) were investigated. Mesomorphic behaviors were analyzed by differential scanning calorimetry (DSC) and mesophase textures were identified by polarized light microscopy (POM). H-bonded assembly was established by FT-IR spectroscopic measurements via Fermi band discussion. Thermal and theoretical factors were predicted for all synthesized complexes by density functional theory (DFT) predictions. The results revealed that all prepared complexes were monomorphic, with a broad range of smectic A phases with a high thermal stability of enantiotropic mesophase. Furthermore, DFT stimulations illustrated the experimental results in terms of the influence of the chain length either of the acid or the base component. Many parameters, such as the calculated stability, the dipole moment and the polarizability of the H-bonded complexes, illustrate how these parameters work together to enhance the smectic mesophases with the obtained stability and range.

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29

Imangazy, A. M. "OBTAINING MESOPHASE PITCHES FROM COAL TAR." Chemical Journal of Kazakhstan 74, no. 2 (June 30, 2021): 14–20. http://dx.doi.org/10.51580/2021-1/2710-1185.24.

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This article presents the results of research on mesophase pitch production from coal tar. The preparation of mesophase pitch was carried out by heat treatment in an argon atmosphere at temperatures of 300, 350, and 400 °C. The resulting carbon pitches were analyzed by scanning electron microscopy, Raman spectroscopy, and energy-dispersive analysis. An increase in the degree of surface degradation and the number of mesophase centers per unit area was observed with an increase in the treatment temperature to 300 °C. At 350 °C, a transition from an isotropic to an anisotropic structure was observed, where the mesophase centers were about 2 μm in size. A similar anisotropic structure was observed for a sample of coal tar obtained at 400 °C, and in some areas, a layered structure was observed, which could be associated with an increase in the graphitization degree of the samples. The particle size of the mesophase increases to 3.5-5 microns. The results of energy dispersive analysis showed that an increase in temperature leads to a decrease in the sulfur content. At 400 °C, sulfur is completely removed from the coal tar pitch composition. A correlation between the heat treatment temperature and the structure of the obtained pitch was established.

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30

Gong, Xin, Xiaodong Liu, and Dong Liu. "Effects of the addition of coal tar pitch-based mesocarbon microbeads on the preparation of mesophase pitch." E3S Web of Conferences 257 (2021): 03015. http://dx.doi.org/10.1051/e3sconf/202125703015.

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Mesophase pitch was prepared by co-carbonization of the hydrocracking tail oil (HCTO) and coal tar pitch-based mesocarbon microbeads (MCMB). The effects of the addition amount of coal tar-based MCMBs on the C/H atomic ratio, softening point, carbon residue, optical texture, aromatic lamellae stacking order degree, and chemical reaction kinetics of mesophase pitch were investigated. The results show that MCMB can be used as a nucleating agent to accelerate the nucleation of mesophase spheres and reduce the energy barriers for the formation of the anisotropic phase. However, excessive MCMB greatly increases the viscosity of the pitch matrix and weakens the mobility of condensed aromatic macromolecules, leading to the formation of mesophase pitch with a mosaic structure and poor lamellar orientation. When the addition amount of MCMB is 5 wt%, the mesophase pitch with a large domain texture, high aromatic lamellar stacking order degree, and low softening point can be formed. This work provides a pathway to efficiently prepare mesophase pitch without catalyst removal.

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31

Koßmehl, Gerhard, Frank Dirk Hoppe, and Barbara Hirsch. "Liquid Crystalline Compounds in the Thiophene Series, Part 6+ Synthesis and Characterization of Azomethines and Vinylenes with Two Mesogenic Groups and Different Alkylene Spacer Lengths." Zeitschrift für Naturforschung B 48, no. 6 (June 1, 1993): 826–43. http://dx.doi.org/10.1515/znb-1993-0619.

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Compounds which have two mesogenic groups with and without terminal alkyl chains containing thiophene systems, were prepared from α.ω-bis(5-formyl-2-thienyl)alkanes (3a-3n) and various aromatic amines or 2-fluorenyl-Wittig-salt (10). The liquid crystalline properties of these compounds were characterized by differential scanning calorimetry (DSC) and polarizing microscopy. Only the series of α.ω-bis{5-[N-(4′-butyloxybiphenyl-4-yl)imino]formyl-2-thienyl}alkanes (7a-71) showed enantiotropic smectic and nematic mesophases. The series of E,E-α.ω-bis[5-(2-fluorenylvinyl)-2-thienyl]alkanes (8a-81) showed enantiotropic nematic mesophases for the compounds with 4 and 6 methylene groups, monotropic nematic mesophases for the compounds with 7—12 methylene groups and no liquid crystalline phases for compounds with 3, 5, 16 methylene groups in the connecting alkylene chain. In contrast to the compounds 8a-81, E-l-(5-butyl-2-thienyl)-2-(2-fluorenyl)ethylene has a smectic mesophase.

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32

Caffrey, Martin, Dianfan Li, Nicole Howe, and Syed T. A. Shah. "‘Hit and run’ serial femtosecond crystallography of a membrane kinase in the lipid cubic phase." Philosophical Transactions of the Royal Society B: Biological Sciences 369, no. 1647 (July 17, 2014): 20130621. http://dx.doi.org/10.1098/rstb.2013.0621.

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The lipid-based bicontinuous cubic mesophase is a nanoporous membrane mimetic with applications in areas that include medicine, personal care products, foods and the basic sciences. An application of particular note concerns it use as a medium in which to grow crystals of membrane proteins for structure determination by X-ray crystallography. At least two variations of the mesophase exist. One is the highly viscous cubic phase, which has well developed long-range order. The other so-called sponge phase is considerably more fluid and lacks long-range order. The sponge phase has recently been shown to be a convenient vehicle for delivering microcrystals of membrane proteins to an X-ray free-electron laser beam for serial femtosecond crystallography (SFX). Unfortunately, the sponge phase approach calls for large amounts of protein that are not always available in the case of membrane proteins. The cubic phase offers the advantage of requiring significantly less protein for SFX but comes with its own challenges. Here, we describe the physico-chemical bases for these challenges, solutions to them and prospects for future uses of lipidic mesophases in the SFX arena.

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33

Tauchi, Lisa, Takahiro Nakagaki, Masahiro Shimizu, Eiji Itoh, Mikio Yasutake, and Kazuchika Ohta. "Discotic liquid crystals of transition metal complexes 49: establishment of helical structure of fullerene moieties in columnar mesophase of phthalocyanine-fullerene dyads." Journal of Porphyrins and Phthalocyanines 17, no. 11 (November 2013): 1080–93. http://dx.doi.org/10.1142/s1088424613500752.

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A homologous series of the phthalocyanine-fullerene dyads, Cn-PcM(OFbaC60) (n = 6, 8, 10, 12; M = Cu , Ni , Co : 3a–3f) have been synthesized to obtain homeotropic alignment at rt and investigate the effects of spacer chain length (n = 6, 8, 10, 12) and central metal ( M = Cu , Ni , Co ) on the mesomorphism. Interestingly, the shorter-spacer-substituted (n = 6, 8; M = Cu ) dyads 3a and 3b showed a hexagonal columnar mesophase (Colh), whereas the longer-spacer-substituted (n = 10, 12; M = Cu , Ni , Co ) dyads 3c–3f showed a tetragonal columnar mesophase (Coltet). Moreover, each of the homologs 3a–3e shows perfect homeotropic alignment in both the Colh and Coltet mesophases at rt. More interestingly, these columnar mesophases gave a very unique XRD reflection peak denoted as Peak H in a very small angle region of 0.8 < 2θ < 2.0 degree. We have established at the first time from our developed two new XRD sample preparation techniques that the Peak H is due to the helical structure of fullerenes around columns formed by one-dimensionally stacked Pc cores. 1D nano array structure of donor and acceptor between two electrodes is recently proposed to obtain higher photoelectric conversion efficiency for organic thin film solar cells. This 1D nano array structure is almost compatible with the present homeotropically aligned Pc- C 60 dyads 3a–3f between two glass plates. Hence, these novel Pc- C 60 dyads 3a–3f may be very suitable to organic thin film solar cells.

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34

Biradar, Shailesh V., Ravindra S. Dhumal, and Anant Paradkar. "Rheological Investigation of Self-emulsification Process." Journal of Pharmacy & Pharmaceutical Sciences 12, no. 1 (February 9, 2009): 17. http://dx.doi.org/10.18433/j30w2p.

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PURPOSE Aim of this study is to investigate the mechanism of self-emulsification through rheological analysis of intermediate liquid crystalline (LC) phase formed during self-emulsification process. METHODS Binary system of tween 80 (T80) and imwitor 742 (I742) was used and different SES were prepared with I742 at 10, 30, 50, 70 and 90% w/w concentration levels. Self-emulsification was monitored by visual observations and droplet size measurement. Mesophases obtained by 50% v/v hydration of SES were utilized for polarizing microscopy, differential scanning calorimetry and rheological studies. RESULTS Good emulsification with nano sized droplets was observed for SES 30% as compared to micron sized droplets for other SES. In polarizing microscopy, formation of intermediate LC phase was observed in all SES. Lamellar phase was evident in 30% SES while other SES exhibited micellar cubic phase. Presence of high level of structurally bound water in thermal analysis confirmed mesophase formation in all SES. In frequency sweep, decrease in elastic modulus, and an increase in phase degree and loss tangent was observed for 30% SES. Exactly opposite trend was seen in other SES. Thus, rheological studies concluded presence of weak and fragile mesophase structure in 30% SES while LC phase structure with little structural buildup was observed in other SES. This weak mesosphere structure in SES 30% presented no or very little resistance against strain induced deformation. Therefore, during emulsification, weak mesophase in SES 30% ruptured with ease and released jet of nanosize droplets compared to coarse droplets for other SES. CONCLUSION This study signifies the effect of viscoelastic properties of intermediate LC phase on self-emulsification performance.

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35

Dai, S., N. Spielberg, and H. Zimmermann. "X-Ray Study of the Mesophase-Mesophase Transition of Octaalkyloxyorthocyclophanes." Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals 303, no. 1 (September 1997): 97–101. http://dx.doi.org/10.1080/10587259708039411.

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36

Meng, Li, Qiumei Wu, Fafu Yang, and Hongyu Guo. "Novel room-temperature thermotropic liquid crystals: synthesis and mesomorphism of gallic–perylene–gallic trimers." New Journal of Chemistry 39, no. 1 (2015): 72–76. http://dx.doi.org/10.1039/c4nj00993b.

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37

Chen, Shi-Lin, Zhi-Cheng Ma, Chang-Ling Fan, Yu-Lin Liang, and Chong Ye. "Study on spinning stability and microstructure of mesophase pitch." Materials Express 10, no. 10 (October 31, 2020): 1711–17. http://dx.doi.org/10.1166/mex.2020.1802.

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The effect of spinning temperature on phase stability, rheological stability, and thermal stability of mesophase pitch (MP), naphthalene-based mesophase pitch (AR) and microstructure of pitch filament were investigated in this study. Results showed that the interface stratification of anisotropic and isotropic phases, local enrichment of isotropic phases and extensive enrichment of isotropic phases existed in the spinning process for mesophase pitch. The local enrichment of isotropic phase was observed in MP and AR at the spinning temperature of 320 °C. The interface stratification of anisotropic and isotropic phases and extensive enrichment of isotropic phases were generated in MP when the spinning temperature reached 340 °C. This phase separation reduced the rheological stability and thermal stability of mesophase pitch and then affected the spinning ability. The inhomogeneous pores were also formed in the MP and AR mesophase pitch filament at the spinning temperature of 340 °C.

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38

Barraza-Burgos, Juan-Manuel. "Effect of pitch petroleum oxidation on mesophase production." CT&F - Ciencia, Tecnología y Futuro 4, no. 5 (May 31, 2012): 33–42. http://dx.doi.org/10.29047/01225383.220.

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This study used two Colombian petroleum pitches (an asphalt and a precipitate) to determine their capacity as precursor of carbonaceous materials. In order to obtain the mesophase, pitches were oxidized at temperature of 350°C and oxidation times of 2; 3 and 5 hours. Oxidized pitches were fractioned with toluene using a ratio of 20 mL Toluene/g of oxidized bitumen. Insoluble material in Toluene (IT) and Tetrahydrofurane (ITHF) were carbonized with nitrogen at 400°C. For the identification of the mesophase, specimens were fabricated with the material obtained from carbonization. For the quantification of the mesophase, a microscope with polarized light filter was used. A total of 500 points were counted. The results showed that the asphalt treated with the longest oxidation time, contained higher concentration of mesophase. By contrast, the precipitate treated with the shortest oxidation time produced higher concentration of mesophase.

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39

Kugatov, P. V., B. S. Zhirnov, and A. E. Eremenko. "Study of Dependence of Softening Point on Mesophase Content of Petroleum Pitches from Heavy Pyrolysis Resin and Decantoil." Chemistry and Technology of Fuels and Oils 625, no. 3 (2021): 28–31. http://dx.doi.org/10.32935/0023-1169-2021-625-3-28-31.

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Samples of petroleum pitches were obtained from heavy pyrolysis resin and decantoil (heavy gas-oil of catalytic cracking) by thermal polycondensation at atmospheric pressure, temperatures of 380–400 and 410–440°С (for resin and decantoil, respectively) and isothermal holding time of 30–480 min. Analysis of the dependence of the softening point on the mesophase content for the obtained samples showed that at the same mesophase content, decantoil pitches exhibit a lower softening point compared to pyrolysis resin pitches, for which, even at 30 % mesophase, the softening point approaches 300°C. This suggests that it is impossible to obtain pitch from pyrolysis resin with high mesophase content without preliminary preparation (for example, by hydrogenation). On the other hand, it has been shown that for pitches from decantoil, it is possible to isolate the mesophase up to 65% or more with a softening point not higher than 250°C.

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40

Meng, Fan Bao, Na Diao, Cui Zhi Zhu, Ri Li, and Hong Mei Gao. "Synthesis and Characterization of Liquid Crystalline Polysiloxanes Containing Terminal Fluoromethyl Groups." Advanced Materials Research 466-467 (February 2012): 500–503. http://dx.doi.org/10.4028/www.scientific.net/amr.466-467.500.

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A series of liquid crystalline (LC) polysiloxanes (PI-PV) were prepared by use of poly(methylhydrogeno)siloxane and two kinds of terminal olefinic monomers. The chemical structures and liquid-crystalline properties of the synthesized materials were characterized by various experimental techniques. From PI to PV, the glass transition temperature and the isotropic temperature decreased slightly with increase of terminal fluoromethyl units in the polymer systems. All the monomers and polymers showed nematic phase with wide mesophase temperature ranges. The polymers PI, PII and PIII displayed single nematic mesophase, but PIV and PV bearing more terminal fluoromethyl units showed another smectic mesophase besides nematic mesophase.

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41

Erdoğan, Buket S., Devrim Atilla, Ayşe G. Gürek, and Vefa Ahsen. "Liquid crystalline alkylthia-substituted novel phthalocyanines: synthesis and characterization." Journal of Porphyrins and Phthalocyanines 18, no. 01n02 (January 2014): 139–48. http://dx.doi.org/10.1142/s1088424613501149.

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Methylene-bridged tetra- and octa-alkylthia substituted metal free- and Ni ( II ) phthalocyanines were synthesized from the corresponding phthalonitrile derivatives in the presence of the anhydrous metal salt ( NiCl 2) or a strong organic base. The new compounds were fully characterized by elemental analyses, UV-vis, IR, NMR and mass spectra. The mesogenic properties of these materials were studied by differential scanning calorimetry, optical microscopy and X-ray diffraction investigations. X-ray diffraction patterns of the mesophase confirmed that the tetra- and the octa-substituted compounds formed hexagonal columnar mesophases (Colh). The mesogenic properties of these compounds were compared to that of their octa alkythia substituted phthalocyanine derivatives in the literature.

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42

Saravanan, Chinnusamy, Mohan Deepa, Palaninathan Kannan, and Sengodan Senthil. "Donor/Acceptor Interaction-assisted Mesophase Formation in Liquid Crystals Containing Azobenzenes and Their Polymers." Zeitschrift für Naturforschung B 63, no. 5 (May 1, 2008): 571–76. http://dx.doi.org/10.1515/znb-2008-0515.

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Azobenzene-based monomers and their polymers containing donor or acceptor groups at terminal positions have been synthesized. The liquid crystalline (LC) mesophase stability of one type of polymer and mixtures of donor or acceptor substituted polymers have been investigated. Mesophase formation and stability of the mixtures were studied using differential scanning calorimetry (DSC) and a hot-stage optical polarizing microscope (HOPM). The mesophase stability of the mixtures was better than those of the individual components. Binary mixture studies of acceptor monomers (a) and donor monomers (d) show that the pure low molecular weight compounds did not form any molecular aggregates and failed to show LC properties, whereas the mixture of donor substituted azobenzene and acceptor substituted azobenzene exhibits LC property. In the case of polymers, the individual acceptors (A) or donors (D) exhibit LC property, and their mixture stabilizes the crystallinity of the mesophase. The results of correlation studies of various proportions of mixtures of a/d and A/D with regard to LC properties and their mesophase stabilities are presented

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43

Cammidge, Andrew N., Isabelle Chambrier, Michael J. Cook, Ernie H. G. Langner, Muhibur Rahman, and Jannie C. Swarts. "Characterization, liquid crystallinity and spin-coated films of some metalated 1,4,8,11,15,18,22,25-octaalkyl tetrabenzo [b,g,l,q][5,10,15]triazaporphyrin derivatives." Journal of Porphyrins and Phthalocyanines 15, no. 09n10 (September 2011): 890–97. http://dx.doi.org/10.1142/s1088424611003793.

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The preparation and characterization of a number of metalated derivatives of 1,4,8,11,15,18,22,25-octahexyl and 1,4,8,11,15,18,22,25-octadecyl tetrabenzotriazaporphyrins (TBTAPs) are reported. The mesophase behavior of the compounds has been characterized by differential scanning calorimetry (DSC) and by polarized light optical microscopy. Mesophase behavior is compared with data for the corresponding phthalocyanine derivatives reported earlier. The temperature range of the mesophase(s) exhibited by the title compounds is generally broader than those of their phthalocyanine analogs. UV-vis data for examples of the TBTAP compounds as spin-coated films reveal differences in the type of molecular packing in the as-deposited films that is largely dependent upon the length of the alkyl chain substituents. On heating, the films undergo molecular reorganizations at temperatures corresponding to the mesophase transitions of bulk material observed by DSC.

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44

Berger, Daniela, Gina Traistaru, and Cristian Matei. "Influence of different templates on the morphology of mesoporous aluminas." Open Chemistry 10, no. 5 (October 1, 2012): 1688–95. http://dx.doi.org/10.2478/s11532-012-0086-2.

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AbstractMesoporous alumina has many environmental applications as catalysts support and adsorption or separation material. We studied the synthesis conditions for the mesoporous alumina formation from aluminum isopropoxide in the presence of anionic (lauric and stearic acid), cationic (cetyltrimethylammonium bromide, CTAB) and non-ionic (triblock poly(ethylene oxide)-poly(propylene oxide)-polyethyleneoxide, P123) templates. The X-ray diffraction data show that the alumina mesophases obtained at 550°C in the presence of fatty acids or P123 have amorphous walls, whereas the samples prepared at 500°C by using CTAB, in alkaline medium are crystalline with a γ-alumina structure. The solvothermal treatment caused the alumina mesophase with crystalline walls to be obtained at 550°C. The samples were investigated by nitrogen adsorption-desorption isotherms and scanning electron microscopy. The obtained alumina mesophases have specific surface areas in the range of 300–450 m2 g−1, narrow pore size distribution, and different morphology depending on the template used in the synthesis.

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45

Thayee Al-Janabi, Omer Y., Ahmed K. Hussein, Emaad T. Bakir Al-Tikrity, Osamah A. Hussein, and Hana’a K. Salih. "Design of new Schiff base polymers containing thiadiazole rings and study of their liquid crystalline behavior." Polymers and Polymer Composites 28, no. 2 (July 24, 2019): 100–111. http://dx.doi.org/10.1177/0967391119865121.

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New liquid crystalline thiadiazole dibenzaldehyde monomers labeled as THDB1–THDB3 were successfully synthesized by alkylation of thiadiazole’s potassium salt with 4-(bromomethyl) benzaldehyde. A number of polymers consisting of thiadiazole and azomethine coded PTDAZ1–PTDAZ5 were synthesized via condensation reaction of the presynthesized monomers THDB1–THDB3 with aromatic diamines. The chemical structures of the prepared materials were confirmed using Fourier-transform infrared spectroscopy and proton nuclear magnetic resonance techniques. The liquid crystalline behavior of the studied monomers and polymers was examined by differential scanning calorimetry and hot stage polarized optical microscopy (POM) techniques. All these compounds were found to demonstrate mesomorphic transitions belonging to smectic and nematic liquid crystals. The studied monomers exhibited fan-like texture of smectic mesophase under POM cooling investigation. Fan-like texture of smectic and nematic mesophases was observed under POM for PTDAZ1 and PTDAZ2, while PTDAZ3 and PTDAZ4 revealed clay and schlieren textures of the smectic and nematic mesophases, respectively, and nematic texture has been found for the polymer PTDAZ5.

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46

Shimizu, Y., B. Heinrich, D. Guillon, M. Shiro, H. Monobe, and K. Oikawa. "Mesophase semiconductors: design for 3D-mesophases with effective paths for electronic charge hopping." Acta Crystallographica Section A Foundations of Crystallography 64, a1 (August 23, 2008): C32. http://dx.doi.org/10.1107/s0108767308099005.

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47

Ariyoshi, Masaaki, Makiko Sugibayashi-Kajita, Ayumi Suzuki-Ichihara, Takayuki Kato, Tenpei Kamei, Eiji Itoh, and Kazuchika Ohta. "Discotic liquid crystals of transition metal complexes 44: synthesis of hexaphenoxy-substituted phthalocyanine derivatives showing spontaneous perfect homeotropic alignment." Journal of Porphyrins and Phthalocyanines 16, no. 10 (October 2012): 1114–23. http://dx.doi.org/10.1142/s1088424612500976.

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We have synthesized novel hexaphenoxy-substituted phthalocyanine derivatives, 2-(12-hydroxydodecyloxy)-3-methoxy-9,10,16,17,23,24-hexakis(3,4-di-n-alkoxyphenoxy)phthalocyaninato copper(II) (abbreviated as Cn(OC12OH)PcCu : n = 10, 12, 14), and investigated their columnar mesomorphism and homeotropic alignment property. These hexaphenoxy-substituted Pc derivatives could be successfully isolated and purified from the mixture products by polarity difference. It was revealed by using polarizing optical microscopic observations, differential scanning calorimetry and temperature-dependent X-ray diffraction studies that each of the hexaphenoxy-substituted Pc derivatives has plural mesophases, and that the tetragonal columnar (Coltet) mesophase shows spontaneous perfect homeotropic alignment between two non-surface-treated glass plates without any defects and polydomain boundaries.

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Alamro, Fowzia S., Hoda A. Ahmed, Magdi M. Naoum, Ayman M. Mostafa, and Asmaa A. Alserehi. "Induced Smectic Phases from Supramolecular H-Bonded Complexes Based on Non-Mesomorphic Components." Crystals 11, no. 8 (August 12, 2021): 940. http://dx.doi.org/10.3390/cryst11080940.

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New non-symmetrical 1:1 supramolecular H-bonded (SMHB) interactions, Ix/II, were designed between the non-mesomorphic fatty acids (palmitic, oleic and linoleic acids) and 4-tetradecyloxyphenylazo pyridine. Mesophase behaviors of the formed complexes were examined via differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). In order to confirm the H-bond interaction formations within the prepared SMHB complexes, FT-IR spectroscopy was established whereby Fermi bands confirm these interactions. Mesomorphic investigations for all complexes indicated that, independent of the terminal alkenyl chains of the natural acids, induced dimorphic smectic phases were observed. The stability of formed mesophases was found to depend on the degree of un-saturation of the terminal alkenyl group of acid component.

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Li, Zhao Feng, Zong Hui Zhou, and Li Fu Shan. "Existence Forms of Magnesium Oxide in Steel Slag by Chemical Phase Separation." Advanced Materials Research 177 (December 2010): 481–84. http://dx.doi.org/10.4028/www.scientific.net/amr.177.481.

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Magnesium oxide solid dissolved in silicate phase, mesophase and RO-phase which are the major constituents of steel slag. The MgO exists in the steel slag with complex forms, which results in the bad soundness of the steel slag. In this paper, the silicate phase and mesophase were separated by salicylic acid methanol solution and potassium hydroxide-sucrose solution respectively and were studied combining with the XRD and SEM. The results show that the silicate phase and mesophase can be fully dissolved, however, the RO phase is not influenced by the two solutions in this process. The content of magnesium oxide existed in different minerals can be detected by chemical analysis. It can be found that the magnesium oxide mainly exists as RO-phase in steel slag, and some of them exist as free state, while only a small quantity of solid dissolve in the silicate phase and mesophase.

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Garland, Andrew D., Geoffrey C. Bryant, Isabelle Chambrier, Andrew N. Cammidge, and Michael J. Cook. "Liquid crystalline properties of unsymmetrically substituted phthalocyanines: structural features leading to nematic mesophase materials." Journal of Porphyrins and Phthalocyanines 18, no. 10n11 (October 2014): 944–49. http://dx.doi.org/10.1142/s1088424614500722.

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A novel homologous series of four 1,4,8,11,15,18-hexakis(pentyl)-22-methyl-25-hydroxyalkylphthalocyanine derivatives with the hydroxyalkyl chain varying from hydroxynonyl through to hydroxydodecyl has been synthesized to investigate the role of the hydroxyalkyl chain in promoting thermotropic liquid crystalline behavior. Polarizing optical miscoscopy reveals that the compound with the shortest hydroxyalkyl chain (hydroxynonyl) exhibits a mesophase with a texture characteristic of a columnar mesophase, common among liquid crystalline phthalocyanine derivatives. However, as the chain is lengthened along the series, there appears a second type of mesophase that shows a schlieren texture. Such a texture is characteristic of a nematic phase and rare among liquid crystalline phthalocyanine derivatives. A fifth compound, the novel 1,4,8,11,15,18-hexakis(pentyl)-22-methyl-25-dodecylphthalocyanine, exhibits only columnar mesophase behavior suggesting that the hydroxyl group at the end of the longer chains of the former compounds is important in developing the nematic phase.

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Journal articles on the topic 'Mesophase'

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