Polyacetylenes Bearing Mesogenic Side Groups: Synthesis and Properties, 1. Mesogenic Substituents with a Short Flexible Spacer

Stagnaro, Paola; Cavazza, B; Trefiletti, Vincenzo; Costa, Giovanna; Gallot, Bernard; Valenti, Barbara

doi:10.1002/1521-3935(20010601)202:10<2065::aid-macp2065>3.0.co;2-5

Cited by 21 publications

(27 citation statements)

References 7 publications

(17 reference statements)

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“…Following the general synthetic methods [4,5], we synthesized the monosubstituted polyacetylene PHBOP. After purification and drying in a vacuum oven, PHBOP in the form of powders were obtained.…”

Section: Methodsmentioning

confidence: 99%

“…For examples, Davey et al [1] and Whitehead et al [2] investigated the polarized photoluminescence (PL) from liquid crystalline polymers. Recently, several research groups synthesized a novel class of side-chain liquid crystalline polyacetylenes by introducing orientable mesogenic pendant onto the rigid backbone of polyacetylene [3][4][5][6]. Their optical characterization has demonstrated that the dilute solutions of these side-chain liquid crystalline polyacetylenes can give off efficient deep-blue or blue PL [5][6][7][8][9][10] although the pristine polyacetylenes can give off weak PL only in the infrared region [11].…”

Section: Introductionmentioning

confidence: 99%

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Origin of the Deep Blue Photoluminescence of a Liquid Crystalline Polymer Poly[(4-Hexylcarbonyl-Biphenyl-4′-Oxy)-1-Propyne]

Huang

Zhai

2009

Molecular Crystals and Liquid Crystals

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Optical absorption and emission properties of a monosubstituted polyacetylene poly[(4-hexylcarbonyl-biphenyl-4 0 -oxy)-1-propyne] have been investigated by means of ultraviolet-visible spectrophotometry, fluorescence spectroscopy, and electronic structure calculations, respectively. Under ultraviolet excitations, dilute tetrahydrofuran solutions of the side-chain polymer can give off deep-blue photoluminescence. Our results have demonstrated that the optical properties of the liquid crystalline polymer are both concentration and temperature dependent. The origin of the deep-blue photoluminescence of polymer can be ascribed to the biphenyl chromophors in its pendants. Comparative studies to a biphenyl-containing liquid crystal give further evidence to our discussion on the origin of the deep-blue photoluminescence of the polymer.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Origin of the Deep Blue Photoluminescence of a Liquid Crystalline Polymer Poly[(4-Hexylcarbonyl-Biphenyl-4′-Oxy)-1-Propyne]

Huang

Zhai

2009

Molecular Crystals and Liquid Crystals

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“…As mentioned above, Hsu and co-workers find that the cis-rich polymers without spacer do not show LC behavior. However, in the study of the influence of short flexible spacer, [80][81][82] Costa and coworkers found that, with only a single methylene spacer, the SCLCPAs can form Sm phases. Such a short spacer cannot decouple the dynamics of main and side-chains.…”

Section: Sheet-like Mspas and Their Smectic Lc Phasesmentioning

confidence: 99%

Molecular Shapes of Monosubstituted Polyacetylenes in their Liquid Crystalline Phases

Liu¹,

Yu²,

Chen³

2009

Macro Chemistry & Physics

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In this short review, we discuss the molecular shapes of monosubstituted polyacetylenes (MSPAs) in their liquid crystalline (LC) phases. Their rigid backbone with high stereoregularity can endow MSPAs with significant shape persistency, which largely determines their LC structures. Helical cis‐cisoidal and cis‐transoidal MSPAs render rod‐like shapes and can form columnar LC (Φ) phases. In the smectic LC (Sm) phases of MSPAs with mesogenic side‐chains, the main chain, with trans‐cisoidal, trans‐transoidal or extended cis‐transoidal conformation, is in fact largely coplanar with the side‐chains, resulting in a sheet‐like molecular shape. From a simple geometric point of view, the rod‐ or sheet‐like MSPA molecules serve as the building block of their LC phases.magnified image

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“…The introduction of orientable, pendant, mesogenic moieties onto a polyacetylene backbone might increase the conjugation in the main chain and yield polymers with permanent coupling between the electroactive properties and order. Recently, the use of a rigid polymer backbone, such as a polyene chain, to prepare side‐chain, liquid‐crystalline polymers has been considered with growing interest by various research groups 1–6. Conjugated polymers with liquid‐crystalline groups in their side chains are currently drawing interest from the viewpoint of multifunctional electrical and optical materials 7–11.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and properties of polyacetylenes with directly attached bis(4‐alkoxyphenyl)terephthalate mesogens as pendants

Chen

Zha

et al. 2006

J. Polym. Sci. A Polym. Chem.

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Liquid‐crystalline, monosubstituted polyacetylenes containing lateral pendants of bis(4‐alkoxyphenyl)terephthalate with no flexible spacers and alkoxy tails {RO, where R is CH3 [P(1)] or C6H13 [P(6)]} were synthesized, and the effects of the backbone structure and alkoxy tails on the properties of the polymers were investigated. The polymerizations of acetylene monomers were carried out with chloronorbornadiene rhodium(I) dimer as a 1,2‐insertion catalyst in toluene. The structures and properties of the monosubstituted polyacetylenes were characterized and evaluated with nuclear magnetic resonance, infrared spectroscopy, thermogravimetry, differential scanning calorimetry, polarized optical microscopy, ultraviolet spectroscopy, and photoluminescence analyses. The molecular weights of the polymers were measured by gel permeation chromatography. The polymer with long tails (p‐hexyloxy), that is, P(6), formed a smectic mesophase upon heating above the melting temperature, but the other one with short tails (p‐methoxy), that is, P(1), could not exhibit liquid crystallinity at elevated temperatures. The steric effect of bulky, liquid‐crystalline mesogens and a direct connection with the main chain prevented the planar conformation of the polyene backbone and, therefore, led to the lower absorption and emission wavelength of the polymers. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2499–2509, 2006

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Polyacetylenes Bearing Mesogenic Side Groups: Synthesis and Properties, 1. Mesogenic Substituents with a Short Flexible Spacer

Cited by 21 publications

References 7 publications

Origin of the Deep Blue Photoluminescence of a Liquid Crystalline Polymer Poly[(4-Hexylcarbonyl-Biphenyl-4′-Oxy)-1-Propyne]

Origin of the Deep Blue Photoluminescence of a Liquid Crystalline Polymer Poly[(4-Hexylcarbonyl-Biphenyl-4′-Oxy)-1-Propyne]

Molecular Shapes of Monosubstituted Polyacetylenes in their Liquid Crystalline Phases

Synthesis and properties of polyacetylenes with directly attached bis(4‐alkoxyphenyl)terephthalate mesogens as pendants

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