Configuration effects of ortho, meta, and para linkages on liquid crystallinity during thin-film polymerization of poly(ester-amide)s

Cheng, Si‐Xue; Chung, Tai‐Shung

doi:10.1002/1099-0488(20000901)38:17<2121::aid-polb20>3.0.co;2-o

Cited by 13 publications

(2 citation statements)

References 12 publications

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“…The T g values of P#TB decrease in the order P4TB > P2TB > P3TB. As expected, the T g value of P4TB with a tert -butyl group attached to the para position of the phenoxy group of the polystyrene side group is higher than those of P2TB and P3TB with ortho- and meta -type attachments, respectively [ 57 ]. The decrease in the T g values of P2TB and P3TB can be attributed to the kinking in the molecular chain due to the ortho and meta linkages, which increases the free volume of the polymer [ 57 ].…”

Section: Resultssupporting

confidence: 56%

“…As expected, the T g value of P4TB with a tert -butyl group attached to the para position of the phenoxy group of the polystyrene side group is higher than those of P2TB and P3TB with ortho- and meta -type attachments, respectively [ 57 ]. The decrease in the T g values of P2TB and P3TB can be attributed to the kinking in the molecular chain due to the ortho and meta linkages, which increases the free volume of the polymer [ 57 ]. In addition, the ortho linkage increases the steric hindrance and decreases the flexibility, leading to higher T g values than those corresponding to the meta linkage [ 58 ].…”

Section: Resultssupporting

confidence: 56%

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Effect of Position and Structure of the Terminal Moieties in the Side Group on the Liquid Crystal Alignment Behavior of Polystyrene Derivatives

2021

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We synthesized a series of polystyrene derivatives containing various side groups, such as the 4-(tert-butyl)-phenoxymethyl, 3-(tert-butyl)-phenoxymethyl, 2-(tert-butyl)-phenoxymethyl, 4-cumyl-phenoxymethyl, and 4-trityl-phenoxymethyl groups, through a polymer modification reaction to examine the liquid crystal (LC) alignment of these derivatives. In general, the vertical LC alignment on polymer films can be affected by the position and structure of the terminal moiety of the polymer side group. For example, the LC cells fabricated with 4-(tert-butyl)-phenoxymethyl-substituted polystyrene having a tert-butyl moiety as a para-type attachment to the phenoxy groups of the polystyrene derivatives exhibited vertical LC alignment, whereas the LC cells prepared from 3-(tert-butyl)- and 2-(tert-butyl)-phenoxymethyl-substituted polystyrene films exhibited planar LC alignment. In addition, the LC cells fabricated from 4-cumyl- and 4-trityl-phenoxymethyl-substituted polystyrene films with additional phenyl rings in the side groups exhibited planar LC alignment, in contrast to the LC alignment of the (tert-butyl)-phenoxymethyl-substituted polystyrene series. The vertical LC orientation was well correlated with the surface energy of these polymer films. For example, vertical LC orientation, which mainly originates due to the nonpolar tertiary carbon moiety having bulky groups, was observed when the surface energy of the polymer was lower than 36.6 mJ/m2.

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Section: Resultssupporting

confidence: 56%

Section: Resultssupporting

confidence: 56%

Effect of Position and Structure of the Terminal Moieties in the Side Group on the Liquid Crystal Alignment Behavior of Polystyrene Derivatives

2021

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Liquid Crystalline Polymers, Main‐Chain

Chung

Cheng

Jaffé³

2001

Encyclopedia of Polymer Science and Technology

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This review covers the most recent study on the nature of thermotropic liquid crystalline polymers (LCPs) and their progress. 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, the 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 the superior mechanical properties. The thermal stability, degradation behavior, and crystallization kinetics of commercial available main‐chain LCPs are recapitulated. Attention is also given to the rheology, polymer blends, micro‐ and nanostructures, and processing of LCPs and their applications.

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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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Configuration effects of ortho, meta, and para linkages on liquid crystallinity during thin-film polymerization of poly(ester-amide)s

Cited by 13 publications

References 12 publications

Effect of Position and Structure of the Terminal Moieties in the Side Group on the Liquid Crystal Alignment Behavior of Polystyrene Derivatives

Effect of Position and Structure of the Terminal Moieties in the Side Group on the Liquid Crystal Alignment Behavior of Polystyrene Derivatives

Liquid Crystalline Polymers, Main‐Chain

Thermotropic Liquid Crystalline Polymers

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