Mesomorphic behaviour of four series of compounds derived from N,N′-dialkanoylbenzene-1,3-diamine

Harada, Yukimasa; Matsunaga, Yoshio; Miyajima, Nobuhiko; Sakamoto, Seiji

doi:10.1039/jm9950502305

Cited by 13 publications

(10 citation statements)

References 13 publications

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“…[7,24,[142][143][144][145][146][147][148][149][150] Die Selbstorganisation aromatischer Amide in flüssigkristallinen Phasen wurde in den späten 1980er Jahren von Matsunaga und Mitarbeitern beschrieben. [142][143][144] Beispielsweise bilden die Verbindungen 36 und 37 kolumnare Flüssigkristallphasen. [142,143] Die Einfüh-rung von Amidgruppen in substituierte Benzolderivate stabilisiert thermotrope Flüssigkristallphasen durch die Bildung eindimensionaler Wasserstoffbrückensysteme.…”

Section: Eindimensionale Offene Aggregateunclassified

“…[142][143][144] Beispielsweise bilden die Verbindungen 36 und 37 kolumnare Flüssigkristallphasen. [142,143] Die Einfüh-rung von Amidgruppen in substituierte Benzolderivate stabilisiert thermotrope Flüssigkristallphasen durch die Bildung eindimensionaler Wasserstoffbrückensysteme. Nuckolls und Mitarbeiter synthetisierten mehrere Triamidobenzol-Derivate mit chiralen Resten.…”

Section: Eindimensionale Offene Aggregateunclassified

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Funktionelle flüssigkristalline Aggregate: selbstorganisierte weiche Materialien

2005

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Dynamische weiche Materialien werden im 21. Jahrhundert an Bedeutung gewinnen. Zwar sind diese Funktionsmaterialien nicht so beständig wie Metalle, Keramiken oder Plastik, dafür reagieren sie aber gut auf externe Reize. Geordnete weiche Materialien können dynamische Funktionen erfüllen. Flüssigkristalle aus selbstorganisierten Molekülen sind ein Beispiel hierfür: Sie eignen sich möglicherweise zum Elektronen‐, Ionen‐ oder Stofftransport sowie als sensorisch, katalytisch, optisch oder biologisch aktive Materialien. Um diese Funktionen auszuschöpfen, benötigt man unkonventionelle Materialentwürfe. Hier beschreiben wir aktuelle Ansätze zur Funktionalisierung von Flüssigkristallen und zeigen, wie das Design von Flüssigkristallen durch supramolekulare Aggregation und Nanophasentrennung zu einer Vielfalt selbstorganisierter Funktionsmaterialien führt.

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Section: Eindimensionale Offene Aggregateunclassified

Funktionelle flüssigkristalline Aggregate: selbstorganisierte weiche Materialien

2005

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“…This polymerization reaction can produce molecules with molecular weights ranging from about 200 to 2000 Da, [2][3][4] or bigger. [5][6][7] The use of petroleum pitches as raw materials for advanced carbon artifacts requires knowledge of its composition and the existing molecular interactions. 2,4 The molecular composition affects the physical properties of the pitch, such as softening point and viscosity, and the physical characteristics of the final products.…”

Section: Introductionmentioning

confidence: 99%

Mesophase evolution in heat-treated solid petroleum pitches

Lima¹,

Lima²,

França³

et al. 2012

J. Braz. Chem. Soc.

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Uma combinação de técnicas analíticas foi utilizada para acompanhar a evolução da mesofase em pixes de petróleo em fase sólida. As amostras foram caracterizadas por dessorção a laser assistida por matriz, seguida de espectrometria de massas por tempo de vôo (MALDI-TOF-MS), ressonância magnética nuclear de 13 C ( 13 C NMR) de alto campo, 1 H NMR de baixo campo, ressonância eletrônica de spin (EPR), microscopia ótica polarizada e análise termogravimétrica (TGA). A análise por MALDI-TOF-MS revelou uma distribuição oligomérica de pesos moleculares no pixe: monomérica (m/z 200 a 400), dimérica (m/z 400 a 650), trimérica (m/z 650 a 950) e tetramérica (m/z 950 a 1600), fator essential para a produção de fibras de carbono, bem como outros compósitos de carbono. Estudos de tempo de relaxação (T 1 ) permitiram a observação de duas grandes áreas: a dos aromáticos e a de mesofase. Estes resultados também mostraram que o tempo de aquecimento aumenta a área de mesofase. Através de medidas não destrutivas de 13 C NMR, foram obtidos os conteúdos de carbonos aromáticos e alifáticos, e também o grau de protonação desses carbonos. A microscopia ótica com luz polarizada mostrou as interfaces entre as regiões anisotrópicas e isotrópicas, bem como o processo de coalescência da mesofase. Os resultados obtidos pelas outras técnicas corroboram com os resultados de MALDI-TOF-MS e NMR.A combination of analytical techniques was used to follow the mesophase evolution of petroleum pitches in the solid phase. The samples were characterized by matrix assisted laser desorption and time of flight analysis by mass spectrometry (MALDI-TOF-MS), high field 13 C nuclear magnetic resonance ( 13 C NMR), low field 1 H NMR, electron spin resonance (EPR), polarized optical microscopy and thermogravimetric analysis (TGA). MALDI-TOF-MS revealed an oligomeric distribution of molecular weights in the pitch: monomeric (m/z 200 to 400), dimeric (m/z 400 to 650), trimeric (m/z 650 to 950) and tetrameric (m/z 950 to 1600), an essential factor for the production of carbon fibers, among other advanced composite of carbon. Relaxation time (T 1 ) studies permitted to observe two large areas: the aromatics and the mesophases. These results also showed that the heating time increases the mesophasic area. Also through direct and non-destructive 13 C NMR measurements, we obtained the content of aromatic and aliphatic carbons, as well as the degree of protonation of these carbons. Optical microscopy with polarized light showed the interfaces between the anisotropic and isotropic regions as well as the process of coalescence of mesophase. The results obtained by the other techniques corroborate the MALDI-TOF-MS and NMR results.

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“…[ 1,2] Recently, hydrogenbonded mesogenic materials have been developed. [3][4][5][6][7] These materials exhibit thermally stable liquid-crystalline phases by the formation of various types of self-organized structures. [3][4][5][6][7] On the other hand, physical gelation of common organic solvents has been reported.…”

Section: Introductionmentioning

confidence: 99%

“…[3][4][5][6][7] These materials exhibit thermally stable liquid-crystalline phases by the formation of various types of self-organized structures. [3][4][5][6][7] On the other hand, physical gelation of common organic solvents has been reported. [8][9][10][11][12][13] Those organic physical gels are microphase-separated materials consisting of organic solvents and fibrous aggregates of low molecular weight gelling agents.…”

Section: Introductionmentioning

confidence: 99%

Physical Gelation of Nematic Liquid Crystals with Amino Acid Derivatives Leading to the Formation of Soft Solids Responsive to Electric Field.

Mizoshita

Kutsuna

Hanabusa

et al. 2000

J. Photopol. Sci. Technol.

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Nematic liquid crystals, 4-(traps-4-pentylcyclohexyl)benzonitrile(SCHB) and 4-cyano-4'-heptyloxybiphenyl (70CB), have been physically gelled due to the formation of hydrogen-bonded networks comprised of amino acid derivatives. The mixtures of nematic liquid crystals and amino acid derivatives exhibit thermoreversible three states, isotropic, isotropic gel, and nematic liquid-crystalline gel, through the phase change of each of components. The gel states are induced by the formation of microphase-separated structures and transition properties of liquid-crystalline solvents in the network structures are maintained. The anisotropic gels of SCHB can respond to electric fields in polyimidecoated liquid crystal cells. The existence of a small amount of gelling agents has great effects on the electro-optic properties. Acceleration of response behavior of the nematic liquid crystal has been achieved by such physical gelation.

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Mesomorphic behaviour of four series of compounds derived from N,N′-dialkanoylbenzene-1,3-diamine

Cited by 13 publications

References 13 publications

Funktionelle flüssigkristalline Aggregate: selbstorganisierte weiche Materialien

Funktionelle flüssigkristalline Aggregate: selbstorganisierte weiche Materialien

Mesophase evolution in heat-treated solid petroleum pitches

Physical Gelation of Nematic Liquid Crystals with Amino Acid Derivatives Leading to the Formation of Soft Solids Responsive to Electric Field.

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