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Journal articles on the topic 'Mesomorphic phase'

Author: Grafiati

Published: 18 May 2024

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1

Ha, Sie-Tiong, and Teck-Leong Lee. "Synthesis and Mesomorphic Properties of New Fluorinated Schiff Base Liquid Crystals." ISRN Materials Science 2014 (January 16, 2014): 1–7. http://dx.doi.org/10.1155/2014/904657.

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Two new compounds, 4-alkanoyloxybenzylidene-4′-fluoroaniline and 4-fluorobenzylidene-4′-n-alkanoyloxyaniline comprising a terminal fluorosubstituent were studied. The fluoro substituent contributes to the molecular polarizability, thus affecting intermolecular interactions and hence resulting in smectic mesomorphism. The mesomorphic properties were studied using differential scanning calorimetry and polarizing optical microscopy techniques. The mesomorphic properties of compounds studied are strongly dependent on the orientation of the imine (CH=N) linkage. The former Schiff base exhibited smectic A phase whereas the latter compound did not display any mesophase. Reversed imine linkage has caused depression of mesomorphic property in the compound studied (4-fluorobenzylidene-4′-n-alkanoyloxyaniline). The mesomorphic properties of the present compounds were compared with other structurally related series to establish the chemical structure-mesomorphic property relationship.

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2

Mirnaya, T. A., G. G. Yaremchuk, and S. V. Volkov. "Phase Diagrams of Binary Systems of Some Alkali Propionates." Zeitschrift für Naturforschung A 48, no. 10 (October 1, 1993): 995–99. http://dx.doi.org/10.1515/zna-1993-1006.

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Abstract The phase diagrams of the binary systems sodium-potassium, sodium-caesium, and potassium-caesium propionates have been investigated by differential thermal analysis and hot-stage polarization microscopy. Smectic liquid crystals in the systems with sodium propionate have been discovered. Liquid crystal formation in binaries of two non-mesomorphic components is explained by latent mesomorphism which is shown to be inherent to both sodium and potassium propionate.

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3

Sharma, Vinay S., and R. B. Patel. "Synthesis of Liquid Crystals with Substituents in Terminal Benzene Cores and their Mesomorphic Behaviour." International Letters of Chemistry, Physics and Astronomy 58 (September 2015): 144–53. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.58.144.

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A new homologous series consisting of thirteen homologues central ester and chalcone linkage with Pentyloxy side chain at terminal benzene ring is synthesized and their mesomorphic properties are studied, with the exception of the methyl, ethyl and propyl homologues. However, the rest of homologues show mesomorphism enantiotropically manner with exhibition of nematic phase. The texture image of the nematic mesophases is observed by optical polarizing microscope equipped with heating stage (POM) is threaded or Schlieren type. An odd-even effect is observed in the nematic-isotropic curve with alternation in transition temperatures. The mesomorphic properties of the novel series are compared with other structurally similar homologous series. Analytical and spectral data confirm the molecular structure of the compounds.

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4

Sharma, Vinay S., and R. B. Patel. "Synthesis of Liquid Crystals with Substituents in Terminal Benzene Cores and their Mesomorphic Behaviour." International Letters of Chemistry, Physics and Astronomy 58 (September 2, 2015): 144–53. http://dx.doi.org/10.56431/p-9j6csf.

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A new homologous series consisting of thirteen homologues central ester and chalcone linkage with Pentyloxy side chain at terminal benzene ring is synthesized and their mesomorphic properties are studied, with the exception of the methyl, ethyl and propyl homologues. However, the rest of homologues show mesomorphism enantiotropically manner with exhibition of nematic phase. The texture image of the nematic mesophases is observed by optical polarizing microscope equipped with heating stage (POM) is threaded or Schlieren type. An odd-even effect is observed in the nematic-isotropic curve with alternation in transition temperatures. The mesomorphic properties of the novel series are compared with other structurally similar homologous series. Analytical and spectral data confirm the molecular structure of the compounds.

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5

Bhola, G. N., and Umed C. Bhoya. "Mesomorphism Dependence on Cis-Trans Configuration and Varying Terminal/Lateral Group." International Letters of Chemistry, Physics and Astronomy 65 (April 2016): 71–79. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.65.71.

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A chalconyl trans vinyl ester homologous series of thermotropic liquid crystals RO-C6H4-CH=CH-COO-C6H4-CH=CH-CO-C6H3(OCH3)2meta-para is synthesized and studied with a view to understand and establish the relation between molecular structure and mesomorphism or mesomorphic behaviors. Novel homologous series consists of thirteen homologues (C1to C18). First five (C1to C5) homologues are nonmesogenic. Rest of the homologues (C6to C18) homologues is mesogenic. Monotropically smectogenic character appears from C6to C10homologue and C12to C18homologues are enantiotropically smectogenic. Nematogenic property is totally absent throughout a series. Textures of smectic phase are of the type smectic A or C. Transition curves of a phase diagram behaved in normal manner. Analytical, spectral and thermal data supports the molecular structures of homologues. Odd-even effect is observed for Sm-I/I-Sm transition curve. Thermal stability for smectic is 93.7 °C and the mesomorphic phase lengths from enantiotropic homologues for smectic from minimum to maximum is 6.0 °C to 28.0 °C at the C12and C18homologue respectively. Series is smectogenic without exhibition of nematic property. The group efficiency order on the basis of thermal stability is derived; from comparative study of present series and analogous series.

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6

KONISHI, TAKASHI, and YOSHIHISA MIYAMOTO. "Polymer Crystallization through Mesomorphic Phase." Sen'i Gakkaishi 75, no. 2 (February 10, 2019): P—103—P—107. http://dx.doi.org/10.2115/fiber.75.p-103.

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7

NISHIDA, KOJI, TAKASHI KONISHI, and TOSHIJI KANAYA. "Mesomorphic Phase in Crystalline Polymer." FIBER 63, no. 12 (2007): P.412—P.416. http://dx.doi.org/10.2115/fiber.63.p_412.

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8

MORIYA, Keiichi, Yasuyuki KAWANISHI, Toshiya SUZUKI, Shinichi YANO, and Meisetsu KAJIWARA. "Mesomorphic Phase Transition in Organophosphazenes." KOBUNSHI RONBUNSHU 56, no. 6 (1999): 390–95. http://dx.doi.org/10.1295/koron.56.390.

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9

Maheta, S. A., G. N. Bhola, and Umed C. Bhoya. "Dependence of Liquid Crystalline Behaviors on Molecular Flexibility." International Letters of Chemistry, Physics and Astronomy 47 (February 2015): 77–86. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.47.77.

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A novel homologous series of thermotropic liquid crystal (LC) has been synthesized with a view to understand and establish the effect of molecular structure on liquid crystal behaviors of a series. The present LC series consist of twelve homologues (C1 to C16); whose mesomorphic properties commence from octyloxy (C8) homologue of a series. C8, C10 and C12 members of a series are monotropic smectic and C14, C16 members are enantiotropically smectogenic. C1 to C7 homologues are nonmesomorphic. Nematogenic property is totally absent. Transition and melting temperatures are determined by an optical polarizing microscopy equipped with a heating stage. Textures of smectic mesophases are focal conic three or two dimensional networking of the type A or C. Cr-I/Sm and Sm-I or I-Sm transition curves behaved in normal manner. Analytical and spectral data confirms the molecular structures of homologues. Thermal stability of smectogenic mesophase is 100.6 oC and mesomorphic phase length is very short (12.9 °C to 15.3 oC). LC properties of a present novel series are compared with the structurally similar homologous series. Present series is partly smectogenic and partly non mesomorphic with poor degree of mesomorphism and middle ordered melting type without exhibition of nematogenic behavior.

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10

Maheta, S. A., G. N. Bhola, and Umed C. Bhoya. "Dependence of Liquid Crystalline Behaviors on Molecular Flexibility." International Letters of Chemistry, Physics and Astronomy 47 (February 24, 2015): 77–86. http://dx.doi.org/10.56431/p-88a000.

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A novel homologous series of thermotropic liquid crystal (LC) has been synthesized with a view to understand and establish the effect of molecular structure on liquid crystal behaviors of a series. The present LC series consist of twelve homologues (C1 to C16); whose mesomorphic properties commence from octyloxy (C8) homologue of a series. C8, C10 and C12 members of a series are monotropic smectic and C14, C16 members are enantiotropically smectogenic. C1 to C7 homologues are nonmesomorphic. Nematogenic property is totally absent. Transition and melting temperatures are determined by an optical polarizing microscopy equipped with a heating stage. Textures of smectic mesophases are focal conic three or two dimensional networking of the type A or C. Cr-I/Sm and Sm-I or I-Sm transition curves behaved in normal manner. Analytical and spectral data confirms the molecular structures of homologues. Thermal stability of smectogenic mesophase is 100.6 oC and mesomorphic phase length is very short (12.9 °C to 15.3 oC). LC properties of a present novel series are compared with the structurally similar homologous series. Present series is partly smectogenic and partly non mesomorphic with poor degree of mesomorphism and middle ordered melting type without exhibition of nematogenic behavior.

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11

Bhola, G. N., and Umed C. Bhoya. "Mesomorphism Dependence on Cis-Trans Configuration and Varying Terminal/Lateral Group." International Letters of Chemistry, Physics and Astronomy 65 (April 6, 2016): 71–79. http://dx.doi.org/10.56431/p-9v83m3.

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A chalconyl trans vinyl ester homologous series of thermotropic liquid crystals RO-C6H4-CH=CH-COO-C6H4-CH=CH-CO-C6H3 (OCH3)2 meta-para is synthesized and studied with a view to understand and establish the relation between molecular structure and mesomorphism or mesomorphic behaviors. Novel homologous series consists of thirteen homologues (C1 to C18). First five (C1 to C5) homologues are nonmesogenic. Rest of the homologues (C6 to C18) homologues is mesogenic. Monotropically smectogenic character appears from C6 to C10 homologue and C12 to C18 homologues are enantiotropically smectogenic. Nematogenic property is totally absent throughout a series. Textures of smectic phase are of the type smectic A or C. Transition curves of a phase diagram behaved in normal manner. Analytical, spectral and thermal data supports the molecular structures of homologues. Odd-even effect is observed for Sm-I/I-Sm transition curve. Thermal stability for smectic is 93.7 °C and the mesomorphic phase lengths from enantiotropic homologues for smectic from minimum to maximum is 6.0 °C to 28.0 °C at the C12 and C18 homologue respectively. Series is smectogenic without exhibition of nematic property. The group efficiency order on the basis of thermal stability is derived; from comparative study of present series and analogous series.

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12

Mirnaya, T. A., V. S. Dradrah, and G. G. Yaremchuk. "Mesophase and Glass Formation in Binary Systems of Caesium and Alkali-Earth Metal Butyrates." Zeitschrift für Naturforschung A 54, no. 12 (December 1, 1999): 685–88. http://dx.doi.org/10.1515/zna-1999-1204.

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Abstract The phase diagrams of the binary systems of non-mesomorphic components such as caesium-mag-nesium, caesium-calcium and caesium-barium butyrates have been studied by differential thermal analysis and hot stage polarization microscopy. Smectic liquid crystals are found in some composition ranges of the binaries with calcium and barium butyrates. The liquid crystal appearance in these systems is explained by the exhibition of latent mesomorphism of caesium butyrate. Glasses are obtained in all systems studied, the formation of vitreous optical anisotropic mesophase being revealed only for binary from caesium and barium butyrates.

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13

Kłosowicz, Stanisław, Jerzy Zieliński, and Zbigniew Raszewski. "Mesomorphic state and types of mesophases." Bulletin of the Military University of Technology 71, no. 1 (March 31, 2022): 115–35. http://dx.doi.org/10.5604/01.3001.0016.1478.

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The paper presents basic types of liquid-crystalline phases obtained in different ways and supermolecular arrangement in those phases. Characteristic features of molecular structure of mesogens are discussed, moreover their influence on liquid-crystalline properties are described too. Examples of the effect of intermolecular interactions on the phase situation of a liquid crystal are given. Keywords: liquid crystals, mesophases, polymorphism, mesogens, molecular structure

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14

Nishida, Koji, and Harutoshi Asakawa. "Mesomorphic Phase of Isotactic Polypropylene ―Part2―." Seikei-Kakou 23, no. 7 (June 20, 2011): 418–20. http://dx.doi.org/10.4325/seikeikakou.23.418.

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15

Caffrey, Martin. "A lipid mesomorphic phase data compilation." BioEssays 5, no. 4 (October 1986): 184. http://dx.doi.org/10.1002/bies.950050412.

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16

Cheng, Rui, Wen Guang Wang, Teng Zhou Yang, Yu Jiang, and Jia Ling Pu. "Mesomorphism of Hexa-Peri-Hexabenzocoronene Discotic Liquid Crystals with Odd-Carbon Alkyl Chains." Advanced Materials Research 554-556 (July 2012): 43–46. http://dx.doi.org/10.4028/www.scientific.net/amr.554-556.43.

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A new HBC derivative HBC-C17containing 6 odd-carbon alkyl chains surrounding the hexabenzocoronene core was synthesized, and investigated as discotic liquid crystal along with HBC-C13and HBC-C15. The thermal behaviors have been investigated by using differential scanning calorimetry (DSC). And mesomorphic phase behavior of HBC-C17was observed by polarizing optical microscopy (POM). A remarkable variation in the phase transition temperatures was observed for these three HBC derivatives (HBC-C13, HBC-C15and HBC-C17). Moreover, the mesomorphism of these HBC derivatives can be compared with HBC-C12, HBC-C14and other HBCs with even carbon alkyl chains, meanwhile the relationship between the length of substitutes and thermal properties of HBCs is also studied.

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17

Ha, S. T., and Y. W. Low. "Synthesis and Phase Transition Behaviours of New Chalcone Derivatives." Journal of Chemistry 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/943723.

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A series of new chalcone derivatives with a general formula of C11H27COOC6H4COCH=CHC6H4X where X=F, Cl, Br, and NO2were well synthesized and crystallized from organic solution. The physical properties as well as the chemical formulations of these compounds were determined by spectroscopic techniques (FTIR, and1H and13C NMR). Differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) techniques were employed to study their transition temperatures and mesophase characteristics. DSC thermograms of compounds with fluoro and nitro substituents displayed direct isotropization and recrystallization during heating and cooling processes. Chloro and bromo analogues exhibited Cr1-to-Cr2transition within the crystal phase region. It was also found that enone linkage showed fewer tendencies to exhibit mesomorphic property compared to imine linkage. However, when enone linkage is combined with other central linkages and additional phenyl rings, it turns conducive to mesomorphism.

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18

Sun, Sha, Wen Cai Xu, Chun Xiu Zhang, and Shi Yong Luo. "Synthesis and Phase Behavior of 4, 4’-Azobisphenol Derivatives." Advanced Materials Research 380 (November 2011): 316–19. http://dx.doi.org/10.4028/www.scientific.net/amr.380.316.

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In this paper, 4, 4’-Azobisphenol was synthesized with three methods which were high temperature reduction, Pb-reduction and diazotize-coupling, and diazotize-coupling was the best way. 4, 4’-Azobisphenol derivatives-1, 2- bis(4-(alloxy/hexyloxy)phenyl) diazene were synthesized through etherification. The structures of these compounds were characterized by the methods of 1H-NMR and FTIR. Phase-transition temperature was measured by DSC, and the phase behaviors were studied by the polarizing microscope. In those derivatives, only1, 2- bis(4-(hexyloxy)phenyl) diazene had mesomorphic phase and mosaic texture. Its mesomorphic phase temperature ranged from 89.3°C to101°C.

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19

Parra, M., Sh Villouta, V. Vera, J. Belmar, C. Zúñiga, and H. Zunza. "Synthesis and Mesomorphic Properties of Azo Compounds Derived from Phenyl-and Thienyl-1,3,4-Thiadiazole." Zeitschrift für Naturforschung B 52, no. 12 (December 1, 1997): 1533–38. http://dx.doi.org/10.1515/znb-1997-1215.

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The synthesis and mesomorphic behaviour of new series of liquid crystals containing 1,3,4- thiadiazole and thiophene rings with azo central bond are reported (series 5a and 5b). All compounds of series 5a exhibit enantiotropic nematic mesophase and the higher homologues (n = 9 - 10) also show a monotropic smectic C phase. Series 5b show dimorphism SC - N (for n = 5 - 7 the SC is monotropic). These series are compared with the Schiff’s bases analogues, the imine bond gives rise to similar liquid crystals phase but larger mesomorphic range.

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20

Solanki, Ravindra, and R. B. Patel. "Study of Mesomorphism Changing on Terminal Side Chain with Different Thioalkyl Group." International Letters of Chemistry, Physics and Astronomy 60 (September 2015): 142–51. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.60.142.

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A novel mesomorphic series is RS-C6H4-COO-C6H4-CO-CH=CH-C6H4-OC18H37(n) (para) of chalconyl ester play double role thermotropic as well as lyotropically bioactive is synthesized and studied with a view to understand and establish the effect on mesomorphism when changing on left thioalkyl chain.the relation between mesomorphism and molecular structure on the basis of molecular rigidity and flex Novel series consists of thirteen homologues of which four homologues (C1 to C3) are non liquid crystal and the rest of the homologues (C5 to C18) are thermotropically enantiotropic nematic absences with smectic property. Thermometric transition temperatures and textures of nematogenic phase are determined by an optical polarizing microscopy equipped with a heating stage (POM).Textures of nematicphas schilieren and threaded type. Cr-N/I and N-I transition curves behaves in as manner with negligible abnormality at C18 homologue in phase diagram of a series.Analytical and spectral data conforms the molecular structure of homologues. Thermal stability for nematic is 123.2 °C whose degree of mesomorphism vary minimum from 4.0°C to a maximum of 24.0 °C, and hence novel series is of middle ordered melting type.

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21

Solanki, Ravindra, and R. B. Patel. "Study of Mesomorphism Changing on Terminal Side Chain with Different Thioalkyl Group." International Letters of Chemistry, Physics and Astronomy 60 (September 30, 2015): 142–51. http://dx.doi.org/10.56431/p-8444j2.

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A novel mesomorphic series is RS-C6H4-COO-C6H4-CO-CH=CH-C6H4-OC18H37(n) (para) of chalconyl ester play double role thermotropic as well as lyotropically bioactive is synthesized and studied with a view to understand and establish the effect on mesomorphism when changing on left thioalkyl chain.the relation between mesomorphism and molecular structure on the basis of molecular rigidity and flex Novel series consists of thirteen homologues of which four homologues (C1 to C3) are non liquid crystal and the rest of the homologues (C5 to C18) are thermotropically enantiotropic nematic absences with smectic property. Thermometric transition temperatures and textures of nematogenic phase are determined by an optical polarizing microscopy equipped with a heating stage (POM).Textures of nematicphas schilieren and threaded type. Cr-N/I and N-I transition curves behaves in as manner with negligible abnormality at C18 homologue in phase diagram of a series.Analytical and spectral data conforms the molecular structure of homologues. Thermal stability for nematic is 123.2 °C whose degree of mesomorphism vary minimum from 4.0°C to a maximum of 24.0 °C, and hence novel series is of middle ordered melting type.

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22

Ong, L. K., and S. T. Ha. "Influence of Linking Group Orientation on Mesomorphism of Two Aromatic Ring Mesogens." Journal of Chemistry 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/864819.

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A new homologous series of alkyl 4-{[(4-chlorophenyl)imino]methyl}benzoates were prepared, and all the members are differentiate by the alkoxy chain length,CnH2n+1O, wheren=2–7, 9, 11, 13, 15. Their phase transition behaviors and mesophase characteristics were studied by differential scanning calorimetry (DSC) and optical polarizing microscopy techniques. DSC thermograms show direct isotropization and recrystallization during heating and cooling processes, respectively. The crystal phase changed directly to dark area textures (isotropic phase) without displaying any mesophase. The mesomorphic properties of compounds studied are strongly dependent on the orientation of the ester linkage. Reversed ester linkage has caused depression of mesomorphic property in the compounds studied.

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23

Fabre, P., C. Casagrande, M. Veyssie, V. Cabuil, and R. Massart. "Ferrosmectics: A new magnetic and mesomorphic phase." Physical Review Letters 64, no. 5 (January 29, 1990): 539–42. http://dx.doi.org/10.1103/physrevlett.64.539.

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24

Lansac, Y., F. Fried, and P. Maïssa. "Dynamics of phase separation in mesomorphic mixtures." Liquid Crystals 18, no. 6 (June 1, 1995): 829–37. http://dx.doi.org/10.1080/02678299508036699.

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25

Wang, Zhi-Gang, Benjamin S. Hsiao, Srivatsan Srinivas, Gary M. Brown, Andy H. Tsou, Stephen Z. D. Cheng, and Richard S. Stein. "Phase transformation in quenched mesomorphic isotactic polypropylene." Polymer 42, no. 18 (August 2001): 7561–66. http://dx.doi.org/10.1016/s0032-3861(01)00286-5.

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26

Konishi, Takashi, Koji Nishida, Go Matsuba, and Toshiji Kanaya. "Mesomorphic Phase of Poly(butylene-2,6-naphthalate)." Macromolecules 41, no. 9 (May 2008): 3157–61. http://dx.doi.org/10.1021/ma702383b.

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27

Kutsumizu, Shoichi, Minoru Yamada, and Shinichi Yano. "Mesomorphic phase transitions of a series of D-phase compounds." Liquid Crystals 16, no. 6 (June 1994): 1109–13. http://dx.doi.org/10.1080/02678299408027881.

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28

Yao, Dan Shu, Jun He, Guo Hua Li, Qian Xu, Ying Gang Jia, and Fan Bao Meng. "Synthesis and Mesomorphism of Novel Star-Shaped Liquid Crystals Containing Donor-Acceptor Groups." Applied Mechanics and Materials 395-396 (September 2013): 72–75. http://dx.doi.org/10.4028/www.scientific.net/amm.395-396.72.

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A new class of three-armed star-shaped liquid crystals 5a-5d were synthesized, they used 1,3,5-trihydroxybenzene as a core, ω-[4-(p-ethoxybenzoloxy) phenoxycarbonyalkyl acid (3a, 3b) and ω-[4-(p-nitrobenzoloxy) phenoxycarbonyalkyl acid (3c, 3d) as mesogenic arms. Their chemical structures were confirmed by FTIR and 1H NMR spectra. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and thermogravimetric analyzer (TG) measurements. The results showed that the three-armed star-shaped liquid crystals exhibited a broad range of liquid crystalline phases at moderate temperature. The mesogenic arm structures obviously affected the phase behavior. As the intermedius alkyl chain of the star-shaped compounds lengthened (from n=4 to n=8), their melting points decreased but mesomorphic temperature ranges increased. The temperatures when 5% weight loss occurred (td) were higher than 300°C, which revealed that the synthesized three-armed liquid crystals had a high thermal stability. Threadlike, droplet and schlieren texture, typical of nematic phase can be observed in the liquid crystalline state during heating or cooling process.

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29

Kovářová, Anna, Svatopluk Světlík, Václav Kozmík, Jiří Svoboda, Vladimíra Novotná, Damian Pociecha, Ewa Gorecka, and Natalia Podoliak. "Unusual polymorphism in new bent-shaped liquid crystals based on biphenyl as a central molecular core." Beilstein Journal of Organic Chemistry 10 (April 7, 2014): 794–807. http://dx.doi.org/10.3762/bjoc.10.75.

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Bent-shaped mesogens possessing a biphenyl as a central core have been synthesized and the role of the terminal chain and the orientation of the ester as a linkage group have been investigated. For the studied molecular core we have established that both parameters play an important role for the mesomorphic properties. The polyfluoroalkyl terminal chain supports the formation of mesophases, and the introduction of a chiral lactate terminal chain destabilizes mesophases for the first type of mutual orientation of ester groups, attached to the central core. On the contrary, for the opposite orientation of esters, the terminal chain has no effect on the mesomorphic properties, and columnar phases have been found for all compounds. A unique phase sequence has been found for the mesogen with the fluorinated chain. A generalized tilted smectics, SmCG, have been observed in a temperature interval between two different lamellar SmCP phases and characterized by X-ray and dielectric measurements. The dielectric spectroscopy data are unique and presented for the first time in the SmCG phase providing new information about the molecular dynamics.

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30

Aguilera, C., M. Parra, and G. Fuentes. "Synthesis and Mesomorphic Properties of Polymethylene-α,ω–bis [2-thio- 5-(4',4"n-alcoxybenzoyIoxy)phenyl]-1,3,4-oxadiazole." Zeitschrift für Naturforschung B 53, no. 3 (March 1, 1998): 367–70. http://dx.doi.org/10.1515/znb-1998-0316.

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Abstract Three homologous series of polymethylene-α,ω-bis[2-thio-5(4′,4″n-alkoxybenzoyloxy)- phenyl]-1,3,4-oxadiazole (series 5 a, b, c), are reported.The compounds have identical mesogenic units at both ends of a spacer (i.e. they are twins). These twins possess a spacer of 6, 8 and 10 carbon atoms joined directly to the oxadiazole ring through sulphur atoms. The lateral alkylic chains vary between 6 and 10 carbon atoms.The presence of enantiotropic and monotropic nematic phase is related to the length of the spacer group. The influence of molecular structure on the mesomorphic properties has been studied. Mesomorphic properties and phase transitions have been determined using polarizing hot-stage microscopy and differential scanning calorimetry.

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31

Altowyan, Abeer S., Hoda A. Ahmed, Sobhi M. Gomha, and Ayman M. Mostafa. "Optical and Thermal Investigations of New Schiff Base/Ester Systems in Pure and Mixed States." Polymers 13, no. 11 (May 22, 2021): 1687. http://dx.doi.org/10.3390/polym13111687.

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New mesomorphic series, 4-hexadecyloxy phenyl-imino-4′-(3-methoxyphenyl)-4″-alkoxybenzoates (An), were prepared and investigated with different thermal and mesomorphic techniques. The synthesized homologous series constitutes four members that differ from each other in the terminal length of flexible chain (n) attached to phenyl ester moiety, which varies between n = 6, 8, 10, and 12 carbons. A lateral CH3O group is attached to the central benzene ring in the meta position with respect to the ester moiety. Molecular structures of all newly prepared homologues were elucidated via FT-IR, 1H and 13C NMR spectroscopy. Mesomorphic and thermal properties were examined by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and the mesophases identified by polarized optical microscopy (POM). DSC and POM examinations revealed that all members of the present series (An) exhibit a purely enantiotropic nematic (N) phase. Comparative evaluations and binary phase diagrams were established between the present homologues and their corresponding shorter one (Bn). The examination revealed that, the length of the flexible alkoxy chain incorporated into the phenylimino moiety is highly effective on the temperature range and stability of the mesophase observed. With respect to the binary mixtures An/Bn, the exhibited N phase showed to cover the whole composition range with eutectic behavior.

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32

Song, H. H., T. C. Do, H. J. Jeon, and K. Tashiro. "Mesomorphic phase in oriented poly(pentamethylene 2,6-naphthalate)." Acta Crystallographica Section A Foundations of Crystallography 67, a1 (August 22, 2011): C422. http://dx.doi.org/10.1107/s0108767311089392.

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33

Do, Thi Cuc, Hye-Jin Jeon, Hyun Hoon Song, Kohji Tashiro, Young Ho Kim, and Moonhor Ree. "Mesomorphic phase in oriented poly(pentamethylene 2,6-naphthalate)." Polymer 51, no. 5 (March 2010): 998–1001. http://dx.doi.org/10.1016/j.polymer.2010.01.040.

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34

Konishi, Takashi, Koji Nishida, and Toshiji Kanaya. "Crystallization of Isotactic Polypropylene from Prequenched Mesomorphic Phase." Macromolecules 39, no. 23 (November 2006): 8035–40. http://dx.doi.org/10.1021/ma060191b.

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35

Al-Mutabagani, Laila A., Latifah Abdullah Alshabanah, Hoda A. Ahmed, Mohamed Hagar, and Khulood A. Abu Al-Ola. "New Symmetrical U- and Wavy-Shaped Supramolecular H-Bonded Systems; Geometrical and Mesomorphic Approaches." Molecules 25, no. 6 (March 20, 2020): 1420. http://dx.doi.org/10.3390/molecules25061420.

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New mesomorphic symmetrical 2:1 supramolecular H-bonded complexes of seven phenyl rings were prepared between 4-n-alkoxyphenylazobenzoic acids and 4-(2-(pyridin-3-yl)diazenyl)phenyl nicotinate. Mesomorphic studies of the prepared complexes were investigated using differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Fermi bands of the formed H-bonded interactions were confirmed by FT-IR spectroscopy. Geometrical parameters for all complexes were performed using the density functional theory (DFT) calculations method. Theoretical results revealed that the prepared H-bonded complexes are in non-linear geometry with U-shaped and wavy-shaped geometrical structures; however, the greater linearity of the wavy-shaped compounds could be the reason for their stability with respect to the U-shaped conformer. Moreover, the stable, wavy shape of supramolecular H-bonded complexes (SMHBCs) has been used to illustrate mesomeric behavior in terms of the molecular interaction. The experimental mesomorphic investigations revealed that all complexes possess enantiotropic smectic C phase. Phases were confirmed by miscibility with a standard smectic C (SmC) compound. A comparison was constructed to investigate the effect of incorporating azophenyl moiety into the mesomeric behavior of the corresponding five-membered complexes. It was found that the addition of the extra phenylazo group to the acid moiety has a great increment of the mesophase stability (TC) values with respect to the monotropic SmC phase of the five aromatic systems to the high stable enantiotropic SmC mesophase.

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36

Bubnov, Alexej, Miroslav Kašpar, Věra Hamplová, Ute Dawin, and Frank Giesselmann. "Thermotropic and lyotropic behaviour of new liquid-crystalline materials with different hydrophilic groups: synthesis and mesomorphic properties." Beilstein Journal of Organic Chemistry 9 (February 25, 2013): 425–36. http://dx.doi.org/10.3762/bjoc.9.45.

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Several new calamitic liquid-crystalline (LC) materials with flexible hydrophilic chains, namely either hydroxy groups or ethylene glycol units, or both types together, have been synthesized in order to look for new functional LC materials exhibiting both, thermotropic and lyotropic behaviour. Such materials are of high potential interest for challenging issues such as the self-organization of carbon nanotubes or various nanoparticles. Thermotropic mesomorphic properties have been studied by using polarizing optical microscopy, differential scanning calorimetry and X-ray scattering. Four of these nonchiral and chiral materials exhibit nematic and chiral nematic phases, respectively. For some molecular structures, smectic phases have also been detected. A contact sample of one of the prepared compounds with diethylene glycol clearly shows the lyotropic behaviour; namely a lamellar phase was observed. The relationship between the molecular structure and mesomorphic properties of these new LCs with hydrophilic chains is discussed.

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37

George, A. K., D. M. Potukuchi, S. H. Al-Harthi, and C. Carboni. "Mesomorphism in a Binary Mixture of Non-mesogens: A Dielectric Spectroscopy Investigation." Zeitschrift für Naturforschung A 59, no. 10 (October 1, 2004): 659–64. http://dx.doi.org/10.1515/zna-2004-1006.

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We report on thermal microscopy and low frequency dielectric relaxation of a liquid crystal formed by mixing cholesterol with 1-hexadecanol. Though both components are non-mesogenic, the mixture is found to exhibit a smectic A phase. A 1 Vp-p a. c signal of 100 kHz was used to study the dielectric response, while the frequency was varied from 5 Hz to 10 MHz for relaxation studies. The dielectric loss in the smectic A phase exhibits a single Debye-type off-centered relaxation in the MHz region. The temperature variation of the relaxation frequency is presented by Arrhenius plots, and the corresponding activation energy is estimated. The temperature variation of the dielectric strength (Δε =ε0 −ε∞) and the distribution parameter α in the smectic phase are estimated. The mesomorphic behavior of binary systems, where both components are non-mesomorphic, is discussed.

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38

Padmaja, S., M. Srinivasulu, and Venkata G. K. M. Pisipati. "Higher Homologues of Mesomorphic Benzylidene Anilines. Manifestation of Smectic Polymorphism." Zeitschrift für Naturforschung A 58, no. 9-10 (October 1, 2003): 573–80. http://dx.doi.org/10.1515/zna-2003-9-1017.

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The synthesis and characterisation of higher homologues of the well-known benzylidene anilines, viz. N-(p-n-tridecyloxy, tetradecyloxy, and hexadecyloxy benzylidene)-p-n-alkylanilines, 13O.m, 14O.m and 16O.m liquid crystalline compounds have exhibited mono, bi and tri phase variant smectic polymorphism. The different liquid crystalline phases are characterized by an optical polarising microscope equipped with a PC based temperature controller. The phase transitions are studied by using differential scanning calorimetry. The results are discussed in the light of the data available on other nO.m compounds.

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39

Kozhevnikov, Valery N., Bertrand Donnio, Benoît Heinrich, and Duncan W. Bruce. "Morphology-driven absorption and emission colour changes in liquid-crystalline, cyclometallated platinum(ii) complexes." Chem. Commun. 50, no. 91 (2014): 14191–93. http://dx.doi.org/10.1039/c4cc06958g.

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Platinum(ii) complexes of 1,3-bis(2-pyridyl)benzene containing two alkyl chains are unexpectedly mesomorphic and capable of changing absorption and emission colour depending on the phase obtained after thermal treatment.

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40

Padmaja, S., M. Ramakrishna Nanchara Rao, P. V. Datta Prasad, and V. G. K. M. Pisipati. "Studies of the Orientational Disorder at the Isotropic to Smectic-F Interface." Zeitschrift für Naturforschung A 60, no. 4 (April 1, 2005): 296–300. http://dx.doi.org/10.1515/zna-2005-0414.

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Abstract Density studies on the isotropic to smectic-F transition in higher homologues of N-(p-nalkoxybenzylidene)- p-n-decylanilines (nO.10) mesomorphic compounds with n = 13, 14 and 15 and corresponding studies on thermal expansion coefficient maxima confirm the first order nature of this transition. The density shows strong pretransitional fluctuations, which are estimated by αeff in the vicinity of the mesomorphic fluctuation dominated non-linear region (FDNLR) of this phase transition. The growth of the density fluctuations across this transition is discussed in the light of data on the same transition in other compounds.

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41

Ahmed, Hoda A., and Muna S. Khushaim. "Nematic Phase Induced from Symmetrical Supramolecular H-Bonded Systems Based on Flexible Acid Core." Crystals 10, no. 9 (September 10, 2020): 801. http://dx.doi.org/10.3390/cryst10090801.

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New symmetrical 1:2 supramolecular H-bonded liquid crystals (SMHBLCs) interactions, A/2Bn, were formed between adipic acid and 4-(4′–pyridylazophenyl) 4″-alkoxybenzoates. Optical and mesomorphic behaviors of the prepared SMHBLC complexes were investigated using differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (XRD). FT-IR spectroscopy was carried out to confirm the H-bond interactions of the prepared complexes via Fermi bands formation. Their photo-physical properties were investigated by UV-spectroscopy and the observed absorbance values were found to be mainly dependent on the length of the terminal alkoxy chain. Mesomorphic behaviour for all A/2Bn complexes revealed that all complexes are dimorphic-exhibiting enantiotropic mesophases with induced nematic phases, except for the long chain terminal complex which exhibits only a monomorphic smectic A phase. In order to investigate the effect of mesogenic core geometry on the mesophase properties, a comparison was established between the mesomeric behaviors of the present complexes and previously reported rigid core acid complexes. Finally, the XRD pattern confirmed the POM and DSC results.

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42

García-Peñas, Alberto, José M. Gómez-Elvira, María L. Cerrada, and Ernesto Pérez. "Dependence of phase transitions on composition in isotactic poly(propylene-co-1-pentene-co-1-hexene) terpolymers." RSC Advances 6, no. 86 (2016): 82907–15. http://dx.doi.org/10.1039/c6ra16575c.

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Several polymorphs (monoclinic, orthorhombic, trigonal and mesomorphic) are observed in metallocenic isotactic poly(propylene-co-1-pentene-co-1-hexene) terpolymers, depending on composition and crystallization conditions.

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43

Alamro, Fowzia S., Hoda A. Ahmed, Mohamed A. El-Atawy, Salma A. Al-Zahrani, and Alaa Z. Omar. "Induced Nematic Phase of New Synthesized Laterally Fluorinated Azo/Ester Derivatives." Molecules 26, no. 15 (July 28, 2021): 4546. http://dx.doi.org/10.3390/molecules26154546.

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A new series of laterally fluorinated mesomorphic compounds, namely 2-fluoro-4-((4-(alkyloxy)phenyl)diazenyl)phenyl 4-substitutedbenzoate (Inx) were prepared and evaluated for their mesophase behavior. The synthesized series constitutes five members that possess different terminally attached polar groups (X). Their molecular structures were confirmed by elemental analyses and both FT-IR and NMR spectroscopy. Examination of the prepared derivatives was conducted via experimental and theoretical tools. Mesomorphic investigations were carried by polarized optical microscopy (POM) and differential scanning calorimetry (DSC). DSC and POM measurements indicated that except for the un-substituted analogue, all other derivatives were purely nematogenic, possessing their nematic (N) mesophase enantiotropically. This is to say that insertions of terminal polar substituents on their mesogenic structures induced the N phase. In addition, the location of lateral and terminal polar moieties played a considerable role in achieving good thermal N stability. Computational calculations were investigated to determine the deduced optimized molecular structures. Theoretical data indicated that both size and polarity of the terminal substituent (X) have essential impact on the thermal parameters and optical properties of possible geometries.

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44

TOSAKA, Masatoshi. "Formation of Mesomorphic Phase and Crystallization in Silicone Rubber." NIPPON GOMU KYOKAISHI 90, no. 7 (2017): 329–32. http://dx.doi.org/10.2324/gomu.90.329.

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45

Goderis, B., M. Basiura, V. B. F. Mathot, J. Sworen, and K. Wagener. "Evidence for a mesomorphic phase in precisely branched polyethylenes." Acta Crystallographica Section A Foundations of Crystallography 62, a1 (August 6, 2006): s263. http://dx.doi.org/10.1107/s010876730609475x.

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46

Jadżyn, J., G. Czechowski, B. Żywucki, C. Legrand, P. Bonnet, and R. Dąbrowski. "Dielectric Properties of Mesomorphic n-TPEB's in Isotropic Phase." Zeitschrift für Naturforschung A 48, no. 8-9 (September 1, 1993): 871–74. http://dx.doi.org/10.1515/zna-1993-8-906.

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Dielectric relaxation studies have been performed for the isotropic phase of a series of mesogenicmolecules of l-[3-n-alkyl-biphenyl]-2-[4-isothiocyanatophenyl]ethane, CnH2n+1-Φ-Φ-CH2CH2-Φ-NCS (n-TPEB), for n = 7, 8 and 9. Two Debye-type dielectric absorption bands have beeninterpreted as corresponding to the rotation around the short and long molecular axis.

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47

Deptuch, Aleksandra, Teresa Jaworska-Gołąb, Monika Marzec, Damian Pociecha, Jakub Fitas, Magdalena Żurowska, Marzena Tykarska, and James Hooper. "Mesomorphic phase transitions of 3F7HPhF studied by complementary methods." Phase Transitions 91, no. 2 (November 3, 2017): 186–98. http://dx.doi.org/10.1080/01411594.2017.1393814.

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48

Koido, Shunsuke, Takahiko Kawai, Shinichi Kuroda, Koji Nishida, Toshiji Kanaya, Makoto Kato, Takashi Kurose, and Katsuhiko Nakajima. "Mesomorphic phase formation of plasticized poly(l-lactic acid)." Journal of Applied Polymer Science 131, no. 2 (August 2, 2013): n/a. http://dx.doi.org/10.1002/app.39762.

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49

Deschenaux, Robert, Jean-Luc Marendaz, Julio Santiago, and John W. Goodby. "Crystal Smectic-B Phase from a Mesomorphic Ferrocene Derivative." Helvetica Chimica Acta 78, no. 5 (August 9, 1995): 1215–18. http://dx.doi.org/10.1002/hlca.19950780514.

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50

Popa, Evelyn, Adelina A. Andelescu, Sorina Ilies (b. Motoc), Alexandru Visan, Carmen Cretu, Francesca Scarpelli, Alessandra Crispini, Florica Manea, and Elisabeta I. Szerb. "Hetero-Bimetallic Ferrocene-Containing Zinc(II)-Terpyridyl-Based Metallomesogen: Structural and Electrochemical Characterization." Materials 16, no. 5 (February 27, 2023): 1946. http://dx.doi.org/10.3390/ma16051946.

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The synthesis, as well as the mesomorphic and electrochemical properties, of a hetero-bimetallic coordination complex able to self-assemble into a columnar liquid crystalline phase is reported herein. The mesomorphic properties were investigated by polarized optical microscopy (POM), differential scanning calorimetry (DSC) and Powder X-ray diffraction (PXRD) analysis. Electrochemical properties were explored by cyclic voltammetry (CV), relating the hetero-bimetallic complex behaviour to previously reported analogous monometallic Zn(II) compounds. The obtained results highlight how the presence of the second metal centre and the supramolecular arrangement in the condensed state pilot the function and properties of the new hetero-bimetallic Zn/Fe coordination complex.

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