Synthesis and properties of thermotropic liquid-crystalline polyesters containing 9,10-diphenylanthracene moiety in the main chain

Uchimura, Makoto; Ishige, Ryohei; Shigeta, Masayuki; Arakawa, Yuki; Niko, Yosuke; Watanabe, Junji; Konishi, Gen‐ichi

doi:10.1007/s11164-012-0658-y

Cited by 11 publications

(17 citation statements)

References 42 publications

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“…Both dyes (Scheme 1) have a rigid central core, which is a good basis for developing LC materials. However, the two outer phenyl rings in DPA could hinder self-assembly [8,9]. 9,10-Bis{4-(4-pentylcyclohexyl)phenyl}anthracene is the only known LC derivative of DPA [8], forming a smectic A mesophase at 277°C [8].…”

Section: Introductionmentioning

confidence: 99%

Sidechain engineering in anthracene derivatives: towards photofunctional liquid crystals

Kerkhof

Allan

McGrath

et al. 2017

IJNT

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A series of anthracene derivatives were synthesised to explore how their sidechain configurations influenced their phase behaviour and thereby guiding the design of photofunctional liquid crystalline materials. In the case of 9,10-diphenylanthracene derivatives, longer and more alkyl sidechains resulted in lower melting temperatures, yet liquid crystallinity was not observed. A novel room-temperature molecular liquid was synthesised based on 9,10-diphenylanthracene, the optical properties of which may be exploited in photonic applications. Liquid crystallinity was observed in one of the derivatives of 9,10-bis(phenylethynyl)anthracene, forming a nematic phase at around 210°C. These results highlight the potential opportunities for photofunctional materials with enhanced properties if liquid crystalline anthracenes can be found with lower phase transition temperatures.

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Section: Introductionmentioning

confidence: 99%

Sidechain engineering in anthracene derivatives: towards photofunctional liquid crystals

Kerkhof

Allan

McGrath

et al. 2017

IJNT

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“…A variety of anthracene derived liquid crystals have been reported in the literature. [44][45][46][47] The central polyaromatic core has been chosen despite its elongation, for its efficient photophysical properties. 37 It has also been exploited in a variety of technological applications such as a light emitting layer for organic light-emitting diode (OLED) devices and as a laser dye for liquid-crystal-lasers.…”

Section: Anthracene Derived Liquid Crystalsmentioning

confidence: 99%

“…37 It has also been exploited in a variety of technological applications such as a light emitting layer for organic light-emitting diode (OLED) devices and as a laser dye for liquid-crystal-lasers. 9,44,48 The liquid crystalline phases exhibited have imparted interesting properties; the close proximity of the molecules causes the π orbitals to overlap, giving rise to high charge-carrier mobilities and enhanced conduction which also would be favourable in an upconversion application. There are two main classes of substitution at the 9,10 8,9 44 and 2,6 37,49 positions of the anthracene ring (Fig.…”

Section: Anthracene Derived Liquid Crystalsmentioning

confidence: 99%

“…8,9,44,50 9,10diphenylanthracene (DPA) and 9,10-bis(phenylethynyl)anthracene (BPEA) exhibit high fluorescence quantum yields and the transition dipole moment of the longest wavelength absorption is polarized parallel to the long axis in these molecules, which gives rise to directionally dependent photophysical effects. 9,44,48 The majority of these 9,10-substituted liquid crystals have mesophase temperatures in the range of 100 − 250 • C. 8,9,44 The polyaromatic core forms the rigid central core of the liquid crystal, which must be compensated for by the use of long flexible chains to allow formation of a liquid crystalline phase.…”

Section: 10-substitutionmentioning

confidence: 99%

“…Hydrogen repulsion between the hydrogen atoms at the 2-and 6-positions on the phenyl rings and the 1-,4-,5-and 8-positions means that the outer phenyl rings sit perpendicular to the central core. 9,44 Although this prevents anthracene dimerization, it may disrupt close packing of the molecules in a mesophase.…”

Section: Dpa Derivativesmentioning

confidence: 99%

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Organised Functional Liquids for Photon Upconversion

Kerkhof¹

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<p>Photon upconversion is a process by which lower energy photons are converted to higher energy photons, which can be achieved by the interaction of two triplet excited states. This process holds potential for wavelength shifting solid films in photovoltaic cells. Not all wavelengths emitted by the sun have sufficient energy to be utilized by such devices. Typical solar cells have a band gap of around 1 µm, however there is a significant amount of energy output by the sun that falls below this threshold. Upconversion could lead to more efficient use of energy by converting these lower energy wavelengths to wavelengths that could be directly absorbed by the solar panel. Upconversion has thus far been harnessed in solution, where diffusion is the limiting factor for the efficiency of the process. However, for technological applications it would be better to create thin solid films. In these films, molecules would have to be brought within the distance on which upconversion occurs, as the process would no longer be defined by diffusion. One way to achieve this would be to create liquid crystalline derivatives of upconversion emitter molecules. This would provide ordering in the system, which would enhance electronic coupling and bring molecules within the scale on which upconversion occurs. The work of this thesis has focused on the synthesis of these organised functional liquids: liquid crystals of common upconversion emitter molecules. 9,10-diphenylanthracene (DPA) and 9,10-bis(phenylethynyl)anthracene (BPEA) are popular emitter molecules, and derivatives of these molecules were synthesized. A variety of alkyl chains were attached with or without phenyl linkers. The alkyl chains would provide entropy to the system in order to induce the formation of liquid crystalline phases. The resulting phase behaviour of these derivatives was studied using differential scanning calorimetry (DSC) and polarised optical microscopy (POM). Eight novel derivatives of DPA and BPEA were synthesized. New information was gained as to the requirements of inducing liquid crystallinity in these dye molecules. Direct addition of chains symmetrically to the central dye molecules did not result in the formation of liquid crystalline phases. Through extension of the central core by an extra phenyl ring a liquid crystalline behaviour was observed. A synthesized derivative of DPA exhibited extreme supercooling, which is one of a few derivatives of 9,10-diphenylanthracene to exhibit a liquid state at room temperature. A derivative of BPEA was synthesized that exhibited formation of a mesophase (liquid crystal phase). These two derivatives were investigated for potential use as a material for upconversion.</p>

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Thermotropic Liquid Crystalline Polymers

Jaffé

Cheng

Chung

et al. 2018

Encyclopedia of Polymer Science and Technology

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Herein we present recent studies on the nature of thermotropic liquid crystalline polymers (LCPs) and their progress. Side‐chain liquid crystals are also discussed briefly, showing the similarities and differences between these closely related molecules. We summarize and review the newly developed thin‐film polymerization technique for the investigation of liquid crystalline formation as a function of monomer moieties, and for the study of reaction kinetics, evolution of liquid crystal texture, and surface energy during polycondensation reactions. We also highlight various modification approaches to yield main‐chain LCPs suitable for conventional processing equipment, without compromising the unique liquid crystalline characteristics and superior mechanical properties. The thermal stability, degradation behavior, and crystallization kinetics of commercially available main‐chain LCPs are recapitulated. Attention is also given to the rheology, polymer blends, micro‐ and nanostructures, processing of LCPs, and their applications. In the past decade, investigations of thermotropic LCPs have decreased from the high interest and publication rate of the latter part of the twentieth century. However, the number of monomer combinations giving rise to main‐chain thermotropic polymers has increased and the origin of LCP rheology and morphology have been elucidated. The most important new work is the invention and description of thermotropic thermosets.

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Synthesis and properties of thermotropic liquid-crystalline polyesters containing 9,10-diphenylanthracene moiety in the main chain

Cited by 11 publications

References 42 publications

Sidechain engineering in anthracene derivatives: towards photofunctional liquid crystals

Sidechain engineering in anthracene derivatives: towards photofunctional liquid crystals

Organised Functional Liquids for Photon Upconversion

Thermotropic Liquid Crystalline Polymers

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