Self-organization behaviours of hemiphasmidic side-chain liquid-crystalline polymers with different spacer lengths

Yang, Xin; Xiang, Zheng; Chen, Sheng; Luo, Hang; Zhang, Ye

doi:10.1039/c7nj00991g

Cited by 9 publications

(3 citation statements)

References 42 publications

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“…As discussed in Section 3.1, many of the polymers employed as interfacial modifiers are flexible organics, which generally have a random walk or Gaussian coil chain shape due to the flexibility of their molecular backbone. 58,193,194 The interfacial thickness tends to be proportional to the molecular weight of polymer, however, it cannot be precisely calculated via the average degree of polymerization of the polymer. Rigid chain structures, i.e.…”

Section: Tailoring the Interfacial Thickness By Organic Rigid Liquid mentioning

confidence: 99%

Interface design for high energy density polymer nanocomposites

et al. 2019

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Section: Tailoring the Interfacial Thickness By Organic Rigid Liquid mentioning

confidence: 99%

Interface design for high energy density polymer nanocomposites

et al. 2019

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“…Mesogen-jacketed liquid crystalline polymers (MJLCPs) proposed by Zhou et al in 1987 have attracted increasing interest for its novel structures and intriguing properties, such as high glass transition temperature, broad temperature range of mesophase, forming a banded texture after mechanical shearing in the liquid-crystal (LC) state and ability to be an ideal rod-forming system. − Crowded, rigid, and bulky side groups have been attached laterally to the main chain through a short spacer or with a single covalent bond in MJLCPs. Poly{2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrenes} (PMPCS) is a typical rigid-polymer in MJLCPs family .…”

Section: Introductionmentioning

confidence: 99%

High Performance Capacitors Using BaTiO₃ Nanowires Engineered by Rigid Liquid-crystalline Polymers

Zhang

Zhou

et al. 2017

J. Phys. Chem. C

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Capacitors that provide high power density have attracted scientific and commercial interest, while often suffering from low energy density. Preparing a core−shell structured ceramic is regarded as a kind of effective method to improve the energy density, which is largely determined by the shell in the interfacial region. However, the current state-of-the-art of interfacial layer modification is predominantly based on utilizing flexible polymers, which are random polymer coils that collapse on the surface of any modified ceramic nanoparticles. Because of the characteristic properties of rigidity and orientation, the liquid-crystalline polymer poly{2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene} (PMPCS) is utilized to engineer the interfacial layer thickness on BaTiO 3 nanowire surfaces via surface-initiated reversible addition−fragmentation chain transfer polymerization (RAFT) method, in this paper. As a result, a high discharged energy density of 7.5 J/cm 3 and an energy efficiency of 55.1% at 300 MV/m are achieved, respectively. The findings proved that rigid liquid-crystalline polymer is a promising modifier to prepare high performance capacitors and to explore the interfacial effect in dielectric nanocomposites.

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“…SCLCPs based on a variety of polymer backbones have been prepared, such as polyacrylates, polymethacrylates, polysiloxanes, polyesters, polyethylene, polyacetylenes, and polysulfones. Typically, SCLCPs are prepared either by free-radical polymerization of vinyl monomers, like acrylate and methacrylates, bearing a mesogenic side group, or via polymer analogous reactions wherein the pendant mesogens are attached to a preformed polymer chain via a quantitative coupling protocol, for instance, via hydrosilylation for preparing liquid crystalline polysiloxanes. , Several studies have investigated the effect of different structural elements, such as nature of the polymer backbone, − flexible side-chain spacer length, − mesogenic units, terminal alkyl chain length, ,− etc., on the mesomorphic properties of conventional SCLCPs. Recently, there has been renewed interest in SCLCPs, specifically to explore the possible synergy of macromolecular chain conformation and mesogen organization; this requires an approach to precisely control the periodicity of the pendant mesogen along the backbone.…”

Section: Introductionmentioning

confidence: 99%

Periodically Spaced Side-Chain Liquid Crystalline Polymers

2020

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The melt-transesterification polymerization of diethyl malonate derivatives bearing a pendant mesogen, with α,ω-alkanediols of varying lengths generated a series of side-chain liquid crystalline polymers, wherein the intervening backbone alkylene spacer segment was systematically varied; the effect of the backbone spacer segment on the liquid crystalline property was examined using differential scanning calorimetry (DSC), X-ray scattering, and polarizing light microscopic investigations. Two different mesogen units, based on 4,4'-dialkoxydiazobenzene or 4,4'-dialkoxybiphenyl, were examined; it was seen that most polyesters derived from the diazobenzene mesogen exhibited a stable nematic mesophase, whereas most of those based on biphenyl transformed directly to an isotropic melt. X-ray scattering studies revealed that the polymers carrying biphenyl units formed a well-ordered lamellar structure in the solid state, which was interpreted as being generated via the zigzag folding of the polymer backbone, thus permitting the pendant mesogens and the folded backbone to occupy alternate layers. Based on the slope of the linear variation of the interlamellar spacing as a function of backbone segment length, it was inferred that the backbone is not in an extended all-trans conformation but is disordered; from the value of the intercept, which roughly corresponded to the length of an extended pendant mesogenic segment, it was inferred that the pendant mesogens were interdigitated. The formation of a highly ordered structure in the solid state appears to drive up the melting transition and preclude the formation of the liquid crystalline (LC) phase in the biphenyl series; however, when a flexible hydrophilic tetra(oxyethylene) spacer was incorporated, the polyester revealed a stable mesophase owing to the significant lowering of the melting transition. Comparison of pairs of isomeric polyesters, one having the mesogen within the pendant segment and the other within the backbone, revealed the strong tendency for the main-chain isomer to exhibit smectic mesophases, whereas the side-chain isomer exhibited a nematic mesophase.

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Self-organization behaviours of hemiphasmidic side-chain liquid-crystalline polymers with different spacer lengths

Abstract: The influence of flexible spacers on unusual self-organization behaviours of side-chain liquid-crystalline polymers containing biphenyl hemiphasmidic mesogens.

Cited by 9 publications

References 42 publications

Interface design for high energy density polymer nanocomposites

Interface design for high energy density polymer nanocomposites

High Performance Capacitors Using BaTiO₃ Nanowires Engineered by Rigid Liquid-crystalline Polymers

Periodically Spaced Side-Chain Liquid Crystalline Polymers

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Self-organization behaviours of hemiphasmidic side-chain liquid-crystalline polymers with different spacer lengths

Abstract: The influence of flexible spacers on unusual self-organization behaviours of side-chain liquid-crystalline polymers containing biphenyl hemiphasmidic mesogens.

Cited by 9 publications

References 42 publications

Interface design for high energy density polymer nanocomposites

Interface design for high energy density polymer nanocomposites

High Performance Capacitors Using BaTiO3 Nanowires Engineered by Rigid Liquid-crystalline Polymers

Periodically Spaced Side-Chain Liquid Crystalline Polymers

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High Performance Capacitors Using BaTiO₃ Nanowires Engineered by Rigid Liquid-crystalline Polymers