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Weißflog, W.; Nádasi, Hajnalka; Dunemann, Ulrike; Pelzl, G.; Diele, Siegmar; Eremin, Alexey; Kresse, H.

doi:10.1039/b104098g

Cited by 209 publications

(120 citation statements)

References 47 publications

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“…[1][2][3] Among them, numerous Schiff base type compounds show rich polymorphism of mesophases. [4] Although most of the materials have alkyl or alkyloxy terminal chains, there are examples with terminal chains containing sulfur, [5] carbonyl, [6] carbonate, [7] or carboxylate [8] moieties. The effect of the connecting groups on the phase behavior was also investigated in detail, and it was found that the sequence of the connecting groups has a decisive role on the mesophase formation.…”

Section: Introductionmentioning

confidence: 99%

Intercalated Smectic A Phases in Banana‐Shaped Liquid Crystals with Carbonate End Groups

et al. 2006

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Novel, symmetrical, bent-core mesogens, namely substituted 1,3-phenylenebis{4'-[(ethoxycarbonyl)oxy]-1,1'-biphenyl}-4-carboxylates, are prepared with carbonate groups at both ends of the molecules. The mesophase properties are investigated for different electron-donating and -withdrawing substituents connected to the central ring at different positions. These compounds exhibit nematic and/or smectic A intercalated (SmA(int)) mesophases. Electro-optical studies show a very significant electric-field-induced biaxiality that is fast (<1 ms) and large (0.03) associated with a high birefringence (0.33 at 500 nm, 10 V mum(-1) field) for the unsubstituted analogue. For one substance this effect is observable from above 100 degrees C down to room temperature. Such electric-field-induced biaxiality may find practical applications in fast electro-optic modulation devices.

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Section: Introductionmentioning

confidence: 99%

Intercalated Smectic A Phases in Banana‐Shaped Liquid Crystals with Carbonate End Groups

et al. 2006

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“…After that liquid crystalline phases formed by bent-core molecules were studied theoretically and experimentally from various aspects (compare, for example, refs. [7][8][9]), but reports of nematic phases formed by bent-core molecules remained scarce [10][11][12][13][14]. In parallel it was pointed out on the basis of a symmetry analysis that for biaxial nematic phases, which are fluid in three dimensions, there are several posa e-mail: brand@uni-bayreuth.de b e-mail: pleiner@mpip-mainz.mpg.de sibilities to have biaxial nematic phases with polar order [15].…”

Section: Introductionmentioning

confidence: 95%

Macroscopic behavior of polar nematic gels and elastomers

2016

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Abstract. We present the derivation of the macroscopic equations for uniaxial polar nematic gels and elastomers. We include the strain field as well as relative rotations as independent dynamic macroscopic degrees of freedom. As a consequence, special emphasis is laid on possible static and dynamic cross-couplings between these macroscopic degrees of freedom associated with the network, and the other macroscopic degrees of freedom including reorientations of the macroscopic polarization. In particular, we find static and dissipative dynamic cross-couplings between strain fields and relative rotations on one hand and the macroscopic polarization on the other that allow for new possibilities to manipulate polar nematics. To give one example each for the effects of a static and a dissipative cross-coupling: we find that a static electric field applied perpendicularly to the polar preferred direction leads to relative rotations while dynamically relative rotations can lead to transverse electric currents. In addition to a permanent network, we also consider the effect of a transient network, which is particularly important for the case of gels, melts and concentrated polymer solutions. A section on the influence of macroscopic chirality is included as well.

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“…The obtained compounds were characterized from the structural point of view ( 1 H NMR, 13 C NMR, MS). All the synthetized Schiff bases presented enantiotropic liquid crystalline properties, with a wide stability of mesophases both on heating (between 63 and 113 °C) and cooling cycles (between 73 and 114 °C) as evidenced by POM and DSC investigations.…”

Section: Discussionmentioning

confidence: 99%

“…10 Among them, the phases B 1 , B 2 and B 6 are the most commonly observed on banana shaped compounds. [11][12][13][14] The smectic liquid crystalline phase separates from isotropic liquid in a rich variety of forms, from classical "batonnets" to filamentary shapes or helical coils in lyotropic systems. From these, more frequently are elongated structures consisting of focal-conic domains.…”

Section: Introductionmentioning

confidence: 99%

Symmetric Bent-core Liquid Crystals of Some Schiff Bases Containing Azo Linkage

Ciobanu¹,

Carlescu²,

Lisă³

et al. 2014

Croat. Chem. Acta

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Abstract. The paper presents the synthesis and liquid crystalline properties of some new symmetric bentcore liquid crystals containing a 1,3-dihydroxybenzene central core disubstituted with mesogenic units consisting of three aromatic rings connected through esteric, azomethinic and azo groups. The wings are ended with terminal acyloxy or alkyloxy chains containing 6 to 10 carbon atoms. Compounds were obtained by the condensation reactions between some 4-((4-alcanoyloxyphenyl)azo)benzaldehydes or 4-((4-alkyloxyphenyl)azo)benzaldehydes with the 1,3-phenylene bis(4-aminobenzoate) core. The new synthesized compounds were characterized from structural point of view ( 1 H NMR, 13 C NMR, MS spectroscopy) and liquid crystalline properties (polarizing optical microscopy and differential scanning calorimetry). All the banana shaped compounds presented enantiotropic liquid crystalline properties, with a wideranging stability of mesophases both on heating and cooling cycles. The synthesized compounds presented a good thermal stability in the existence range of the mesophases as evidenced by thermogravimetric studies. (doi: 10.5562/cca2150)

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Cited by 209 publications

References 47 publications

Intercalated Smectic A Phases in Banana‐Shaped Liquid Crystals with Carbonate End Groups

Intercalated Smectic A Phases in Banana‐Shaped Liquid Crystals with Carbonate End Groups

Macroscopic behavior of polar nematic gels and elastomers

Symmetric Bent-core Liquid Crystals of Some Schiff Bases Containing Azo Linkage

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