Effect of Molecular Structure on Mesomorphism.11.<sup>1</sup> A Siamese Twin Liquid Crystal Having Two Independently Smectogenic Conformations

Griffin, Anselm C.; Buckley, Neal W.; Hughes, William E.; Wertz, David L.

doi:10.1080/01406568108072519

Cited by 35 publications

(11 citation statements)

References 5 publications

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“…Already in 1927, Vorländer (Vorländer 1927) synthesized dimers of 1,7-bis(4-alkyloxyphenyl-4'-azophenyl)alkane dioates and noted that the nematic-to-isotropic transition temperature depends strongly on the parity of the number x of carbon atoms in the flexible link connecting two rigid rod-like cores. Similar odd-even effect was reported for other liquid crystalline dimers by Rault, Liebert and Strzelecki (Rault, Liébert, and Strzelecki 1975) and by Griffin (Griffin et al 1981).…”

Section: IVsupporting

confidence: 88%

“…These difficulties renewed the interest to explore dimers, trimers, and other oligomers, with molecular weights intermediate between that of polymers and small molecules, as "prepolymer ptototypes" (G.R. Luckhurst 1995) (Griffin et al 1981). Already in 1927, Vorländer (Vorländer 1927) synthesized dimers of 1,7-bis(4-alkyloxyphenyl-4'-azophenyl)alkane dioates and noted that the nematic-to-isotropic transition temperature depends strongly on the parity of the number x of carbon atoms in the flexible link connecting two rigid rod-like cores.…”

Section: IVmentioning

confidence: 99%

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Physics of liquid crystals of bent-shaped molecules

2018

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Thermotropic liquid crystals can be formed by various molecular shapes, some discovered over 125 years ago. The simplest and most-studied liquid crystals are made of rodshaped molecules and led to today's omnipresent LCDs. While applied scientists and engineers have been perfecting LCDs, a large group of liquid crystal scientists have become excited about liquid crystals of bent-shaped (banana-shaped) molecules. These compounds were first reported 20 years ago, and since then have taken center stage in current liquid crystal science. The "banana-mania" is due to the fact that even a small kink in the molecular shape leads to fundamentally new properties and phases. In this review we summarize the large variety of novel structures and physical properties, and describe the underlying physics. We emphasize that macroscopic properties depend on both the shape of the molecules and the flexibility of the central core. Most rigid bent-core molecules form smectic and sometimes columnar structures; only a minority forms nematic phases. By contrast, most flexible bent-core molecules form nanostructured nematic phases, including the twist-bend nematic phase discovered very recently.

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Section: IVsupporting

confidence: 88%

Section: IVmentioning

confidence: 99%

Physics of liquid crystals of bent-shaped molecules

2018

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“…A decyl (n ¼ 10) derivative with longer chain is the only one described in literature. In 1981 Griffin et al [7] reported only the presence of the smectic C phase in this compound.…”

Section: Introductionmentioning

confidence: 97%

Smectic polymorphism of 4-decyloxybenzylidene- 4′-alkyloxyanilines and their mixtures with polar standards of mesophases

2007

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This article describes liquid crystalline properties of the homologous series of 4-decyloxybenzylidene-4 0 -alkyloxyanilines. Based on the polarization microscopy (POM and TOA methods) and the calorimetric (DSC) measurements a rich polymorphism has been detected. Investigated compounds exhibit nematic, smectic A, smectic C, smectic B, smectic I and G (smectic G) mesophases with their characteristic configurations. The presence of these mesophases was confirmed by the miscibility method, using 4-heptyloxybenxylidene-4 0 -pentylaniline as a mesophase reference. Nine other smectic standards with different polarity have been applied in order to investigate their influence on the mesophase stability.

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“…A literature survey reveals that the H-shaped dimesogenic compounds are scanty. Griffin et al [6,7] reported the first compounds of ligated twins in which two mesogenic units are connected by methylene spacer exhibiting monotropic smectic C and nematic phases. Weissflog et al [8] have synthesized new sulphur-containing twins.…”

Section: Introductionmentioning

confidence: 99%

Azoester-based H-shaped symmetrical mesogenic dimers containing – CH₃/–OCH₃terminal substituent

2011

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Two extensive homologous series of H-shaped symmetrical dimers were synthesized and their thermotropic properties studied by differential scanning calorimetry and on a hot-stage of a polarizing microscope. These compounds consist of two mesogenic units of azoester interconnected through flexible spacers (n ¼ 4) resulting in the structure of 'H-shaped' dimeric compounds. The difference between the two series is in the structure of terminal substituents (-CH 3 for series I and -OCH 3 for series II) attached on the azoester mesogens at one terminus. All these compounds were found to be smectogenic. The effect of different terminal substituents on mesomorphism is discussed. The trans-azobenzene groups of the H-shaped dimeric compounds display a high-intensity -* transition at about 365 nm and a low-intensity -* transition at around 460 nm, therefore, photochromism can be achieved by the introduction of the azo linkage to the H-shaped dimeric compounds.

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Effect of Molecular Structure on Mesomorphism.11.¹ A Siamese Twin Liquid Crystal Having Two Independently Smectogenic Conformations

Cited by 35 publications

References 5 publications

Physics of liquid crystals of bent-shaped molecules

Physics of liquid crystals of bent-shaped molecules

Smectic polymorphism of 4-decyloxybenzylidene- 4′-alkyloxyanilines and their mixtures with polar standards of mesophases

Azoester-based H-shaped symmetrical mesogenic dimers containing – CH₃/–OCH₃terminal substituent

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Effect of Molecular Structure on Mesomorphism.11.1 A Siamese Twin Liquid Crystal Having Two Independently Smectogenic Conformations

Cited by 35 publications

References 5 publications

Physics of liquid crystals of bent-shaped molecules

Physics of liquid crystals of bent-shaped molecules

Smectic polymorphism of 4-decyloxybenzylidene- 4′-alkyloxyanilines and their mixtures with polar standards of mesophases

Azoester-based H-shaped symmetrical mesogenic dimers containing – CH3/–OCH3terminal substituent

Contact Info

Product

Resources

About

Effect of Molecular Structure on Mesomorphism.11.¹ A Siamese Twin Liquid Crystal Having Two Independently Smectogenic Conformations

Azoester-based H-shaped symmetrical mesogenic dimers containing – CH₃/–OCH₃terminal substituent