Hexagonal Columnar.<i>cis, cis</i>-(3,5-dihydroxycyclohexyl)-3,4,5-tris(alkoxy)benzoates Thermal behaviour and water absorption

Lattermannr, Günter; Staufer, Günter; Brezesinski, Gerald

doi:10.1080/02678299108036423

Cited by 26 publications

(6 citation statements)

References 21 publications

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“…Increasing the number of aliphatic chains grafted to a rigid core or even to a nonanisometric but distinct polar molecular part leads to an increase in the volume fraction of the lipophilic aliphatic region. Nonlamellar mesophases such as columnar or cubic can result, as has been successfully demonstrated, e.g., for polycatenar and swallow-tailed mesogens, for taper-shaped polyhydroxy amphipiles, , and for cone-shaped dendrimers …”

Section: Introductionmentioning

confidence: 75%

Hydrogen-Bonded Polyphilic Block Mesogens with Semiperfluorinated Segments

Kohlmeier

Janietz

2005

Chem. Mater.

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Two 2,4-diamino-6-phenyl-1,3,5-triazines carrying either one or two alkoxy chains at the phenyl substituent have been investigated in binary mixtures with two-chain partially fluorinated benzoic acids. Equimolar compositions of the complementary molecular species form discrete hydrogen-bonded dimeric supermolecules. The dimers organize to infinite ribbons of parallel aligned H-bonded polar aromatic cores that are separated by mixed aliphatic/fluorinated regions. The cross-sectional shape of the ribbon aggregates and, therefore, the two-dimensional lattice symmetries of the ribbon phases, rectangular or oblique, are defined by the number of alkoxy chains of the triazine component. Docking of 2 or 3 equiv of the semiperfluorinated benzoic acids to the diaminotriazine core leads to H-bonded aggregates with a circular cross-sectional shape and, consequently, to the formation of columnar phases on a two-dimensional hexagonal lattice.

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Section: Introductionmentioning

confidence: 75%

Hydrogen-Bonded Polyphilic Block Mesogens with Semiperfluorinated Segments

Kohlmeier

Janietz

2005

Chem. Mater.

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“…Ordered discotic networks with stabilized Φ mesophases using cross-linkable chain ends have also been reported . Recent work has shown that some nondisk molecules can be self-assembled into Φ phases. − Columnar phase formation in numerous LC polymers with rodlike mesogens has also been reported. − …”

Section: Introductionmentioning

confidence: 98%

“…Disklike molecules intrinsically possess a flat, rigid, and rotationally symmetric core connected with flexible tails. The core structures are commonly constructed by a single phenylene group, , several phenylene groups, − metal ion complexes, − or self-assembled disk-shaped systems. − The flexible tails, which are alkyl chains in most cases, sometimes bearing functional end groups, are necessary to form discotic LC phases.…”

Section: Introductionmentioning

confidence: 99%

Liquid Crystalline and Monotropic Phase Behaviors of 2,3,6,7,10,11-Hexa(4‘-octyloxybenzoyloxy)triphenylene Discotic Molecules

Tang

Zhang

et al. 2000

Chem. Mater.

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Multiple phase transitions and monotropic phase behavior are observed in a discotic liquid crystal, 2,3,6,7,10,11-hexa(4‘-octyloxybenzoyloxy)triphenylene (HOBT-C8). Detailed phase structural analyses using wide-angle X-ray diffraction and electron diffraction show that, in addition to a discotic nematic (ND) phase at high temperatures, a rectangular columnar (ΦR) phase and an orthorhombic crystalline (KI) phase developing sequentially upon cooling can be identified. A crystalline (KII) phase with a higher melting temperature than that of the KI phase forms during heating. Therefore, the KI phase represents a metastable phase with respect to the KII phase, and the more stable KII phase can be bypassed during cooling at relatively fast cooling rates. The KI phase is thus monotropic with respect to the KII phase at relatively slow heating rates. The optical texture of each phase can be distinguished from polarized light microscopy. A relationship between Gibbs free energy and temperature for different phases can be constructed, which thermodynamically and kinetically represents these multiple phase transitions and the monotropic phase behavior of the KI phase.

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“…Self-assembly of discotic molecules consisting of a disk-shaped aromatic core and peripheral flexible side chains occurs through microsegregation between the aromatic core and the peripheral chains in bulk − or in organic solvents. − Noncovalent interactions such as π−π interactions, hydrogen bondings, and solvophobic effects are the main driving forces for the microsegregation.…”

Section: Introductionmentioning

confidence: 99%

Molecular Aggregation of Disklike Benzenetricarboxamides Containing Diacetylenic Groups in Bulk and Organic Solvents

2004

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We prepared disklike tris(4-alkylbutadiynylphenyl)-1,3,5-benzenetricarboxamide and tris[4-(4-alkyloxyphenyl)butadiynylphenyl]-1,3,5-benzenetricarboxamide, where three phenyl diacetylenic and diphenyl diacetylenic groups are connected to a benzene ring through amide linkages, respectively. The structures of self-assembled substances were investigated by using transmission electron microscopy, scanning electron microscopy, and X-ray diffraction techniques. All the compounds were highly viscous in melt states, and only compound 9 having three phenyl diacetylenic groups and hexyl tails showed a thermotropic mesophase on cooling. The compound with three diphenyl diacetylenic groups and dodecyloxy tails (13) formed a stable gel in THF/cyclohexane. The IR and X-ray analyses showed that in the gel state molecules were assembled into a rectangular columnar lattice and held each other by hydrogen bondings between amide groups. The compound with tetradecyloxy tails (14) formed stable colloidal particles in cyclohexane. The UV irradiation of 13 in a gel and 14 in a colloidal particle did not result in a long conjugated polymer because of the inappropriate alignment of diacetylenic groups for the topochemical polymerization.

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Hexagonal Columnar.cis, cis-(3,5-dihydroxycyclohexyl)-3,4,5-tris(alkoxy)benzoates Thermal behaviour and water absorption

Cited by 26 publications

References 21 publications

Hydrogen-Bonded Polyphilic Block Mesogens with Semiperfluorinated Segments

Hydrogen-Bonded Polyphilic Block Mesogens with Semiperfluorinated Segments

Liquid Crystalline and Monotropic Phase Behaviors of 2,3,6,7,10,11-Hexa(4‘-octyloxybenzoyloxy)triphenylene Discotic Molecules

Molecular Aggregation of Disklike Benzenetricarboxamides Containing Diacetylenic Groups in Bulk and Organic Solvents

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