Synthesis and characterization of chiral smectic side-chain liquid crystalline elastomers containing nematic and chiral mesogens

Jiang, Ying; Ye, Cong; Zhang, Baoyan

doi:10.1039/c6nj02001a

Cited by 10 publications

(5 citation statements)

References 42 publications

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“…The results show that S-CL presents the typical broken fan-shaped texture of smectic phase liquid crystal morphology. 29 The broken fan-shaped texture of S-CL appeared when the temperature changed from 53 °C to 115 °C during heating, which showed the existence of a smectic phase. Subsequently, the broken fan-shaped texture began to disappear gradually as the temperature was increased to 135 °C.…”

Section: Polymer Chemistry Papermentioning

confidence: 98%

High intrinsic thermally conductivity side-chain liquid crystalline polysiloxane films grafted with pendent difunctional mesogenic groups

et al. 2022

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Section: Polymer Chemistry Papermentioning

confidence: 98%

High intrinsic thermally conductivity side-chain liquid crystalline polysiloxane films grafted with pendent difunctional mesogenic groups

et al. 2022

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“…The work on LC‐polysiloxanes started with homopolymers but extended later on to copolymers, in which only a part of the dimethyl‐siloxane units on the polymer chain are substituted with mesogens (so many dimethyl‐siloxane units, which are poorly compatible with the mesogens, are present in the polymer backbone). [ 59–65,92–96 ] This was done to decrease the glass transition as far as possible below room temperature and—in fact—LC phases in the region around room temperature could be achieved. [ 62,92 ] Thereby it was recognized that these copolymers—the so called “diluted” polysiloxanes—were still LC despite the low amounts of mesogens.…”

Section: Lc‐side Chain Polymers With Statistically Incorporated Non Miscible Unitsmentioning

confidence: 99%

LC‐Polymers and Smectic Phases with Special Substructures/Nanophase Segregation

Zentel

2021

Macro Chemistry & Physics

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Liquid crystalline (LC) polymers find still a lot of interest, whereby the focus is—at present—on LC‐elastomers with different phases and their application for mechanical actuation. While the LC‐phases in LC‐polymers can—generally—be well described in analogy to their low molar mass counterparts, some special properties became evident for some systems with smectic phases. They are related to the modulation of the nanophase segregation within the smectic layers and include often the formation of sublayers consisting of poorly compatible parts of the polymer like bulky (=non mesogenic) units, ionic groups, or poorly miscible parts of the main chain (e.g., polysiloxanes). Such a behavior can be found for semiflexible LC‐main chain polymers and for LC‐side chain polymers. Here the authors i) describe polymers for which such a modification of the smectic structure is observed, ii) discuss the origin of the deviation, and iii) describe possible application for the design of functional materials. The formation of the substructures can allow, for example, a mixing of the LC‐polymers with other polymers, which have a good affinity to the second sublayer. It also allows it to separate, to some extent, the network structure from the packing of the mesogens in LC‐polysiloxanes.

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“…Liquid-crystal (LC) elastomers are promising advanced materials in which the orientation of the mesogens is strongly coupled to the polymer network; thus, electro-, mechano-, or thermo-responsive effects on the macroscopic shape and the microscopic molecular orientation can be observed simultaneously [10][11][12][13][14][15][16][17][18]. Notably, chiralnematic (N*) LC elastomers have unique optical properties based on the helical structure of the N* LC system [19][20][21]. N* LC elastomers spontaneously form a helically twisted molecular orientation, with the orientational direction of the mesogens rotating along the helical axis [22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Environmentally Stable Chiral-Nematic Liquid-Crystal Elastomers with Mechano-Optical Properties

Hisano

Kimura

et al. 2021

Applied Sciences

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Chiral-nematic liquid crystal (N* LC) elastomers exhibit mechano-optical responsive behavior. However, practical sensor applications have been limited by the intrinsic sensitivity of N* LC elastomers to environmental conditions, such as temperature. Although densely cross-linked LC network polymers exhibit high thermal stability, they are not proper for the mechanical sensor due to high glass transition temperatures and low flexibility. To overcome these issues, we focused on enhancing thermal stability by introducing noncovalent cross-linking sites via intermolecular interactions between LC molecules bonded to the polymer network. N* LC elastomers with a cyanobiphenyl derivative as a side-chain mesogen exhibited mechano-optical responsive behavior, with a hypsochromic shift of the reflection peak wavelength under an applied tensile strain and quick shape and color recovery owing to high elasticity. Notably, the N* LC elastomers showed high resistance to harsh environments, including high temperatures and various solvents. Interactions, such as π–π stacking and dipole–dipole interactions, between the cyanobiphenyl units can act as weak cross-links, thus improving the thermal stability of the LC phase without affecting the mechano-optical response. Thus, these N* LC elastomers have great potential for the realization of practical mechano-optical sensors.

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Synthesis and characterization of chiral smectic side-chain liquid crystalline elastomers containing nematic and chiral mesogens

Abstract: A novel series of siloxane-based chiral smectic side-chain liquid crystalline elastomers containing nematic and chiral mesogens were fabricated through synthesis involving a one-step hydrosilication reaction via a liquid crystalline crosslinking agent containing smectic and nematic phases.

Cited by 10 publications

References 42 publications

High intrinsic thermally conductivity side-chain liquid crystalline polysiloxane films grafted with pendent difunctional mesogenic groups

High intrinsic thermally conductivity side-chain liquid crystalline polysiloxane films grafted with pendent difunctional mesogenic groups

LC‐Polymers and Smectic Phases with Special Substructures/Nanophase Segregation

Environmentally Stable Chiral-Nematic Liquid-Crystal Elastomers with Mechano-Optical Properties

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