Synthesis and structure of polysiloxane liquid crystalline elastomers with a mesogenic crosslinking agent

Jia, Ying‐Gang; Zhang, Baoyan; Tian, Ming; Pan, Wei

doi:10.1002/app.20604

Cited by 16 publications

(6 citation statements)

References 30 publications

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“…They discussed the effect of mechanical deformation on the mesophase stability, and found an increase of the phase transformation temperature with stress as predicted by Landau-de Gennes theory [14][15][16]. Since then, a wide range of synthetic side-chain elastomers have been described in literature [17][18][19][20][21]. 0032 On the other hand, fewer papers were published on the synthesis and characterization of main-chain LCEs [22][23][24][25].…”

Section: Introductionmentioning

confidence: 98%

Liquid crystalline elastomers based on diglycidyl terminated rigid monomers and aliphatic acids. Part 1. Synthesis and characterization

Ambrogi

Giamberini

Cerruti

et al. 2005

Polymer

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Liquid crystalline elastomers (LCEs) were prepared by reacting rigid-rod mesogenic epoxy monomers with aliphatic diacids of variable length. The influence of acid and nature of epoxy monomer on the mechanism of network growth was investigated through DSC, FT-IR, MALDI, 1 H and 13 C NMR and rheological experiments. Depending on the nature of epoxy monomer, different mechanisms of network growth occurred, which were responsible for the formation of elastomers with different extent of branching.Clearing temperatures, enthalpies and entropies, and the nature of mesophases were also analyzed through DSC and X-ray diffraction, carried out on unstrained elastomers. It was found that both the rigid-rod mesogens and the aliphatic portions of carboxylic acids contribute to stabilize the mesophase. Moreover, upon stretching, all the LCEs exhibited the polydomain-to-monodomain transition, which is typical of this class of materials. q

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Section: Introductionmentioning

confidence: 98%

Liquid crystalline elastomers based on diglycidyl terminated rigid monomers and aliphatic acids. Part 1. Synthesis and characterization

Ambrogi

Giamberini

Cerruti

et al. 2005

Polymer

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“…Many functional properties of LCEs rely on the reversible anisotropic–isotropic transition associated with LC order. Numerous studies have shown that T i can be correlated to the cross‐link density in hydrosilylation‐based LCE systems . High cross‐link densities of the network can disrupt the heat fusion and lower T i , leading to a less stable liquid‐crystalline phase, where lightly cross‐linking hardly affects T i .…”

Section: Introductionmentioning

confidence: 99%

Thiol‐acrylate main‐chain liquid‐crystalline elastomers with tunable thermomechanical properties and actuation strain

Saed

Torbati

Starr

et al. 2016

J Polym Sci B Polym Phys

119

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The purpose of this study was to investigate the influence of cross‐linking on the thermomechanical behavior of liquid‐crystalline elastomers (LCEs). Main‐chain LCE networks were synthesized via a thiol‐acrylate Michael addition reaction. The robust nature of this reaction allowed for tailoring of the behavior of the LCEs by varying the concentration and functionality of the cross‐linker. The isotropic rubbery modulus, glass transition temperature, and strain‐to‐failure showed strong dependence on cross‐linker concentration and ranged from 0.9 MPa, 3 °C, and 105% to 3.2 MPa, 25 °C, and 853%, respectively. The isotropic transition temperature (Ti) was shown to be influenced by the functionality of the cross‐linker, ranging from 70 °C to 80 °C for tri‐ and tetra‐functional cross‐linkers. The magnitude of actuation can be tailored by controlling the amount of cross‐linker and applied stress. Actuation increased with increased applied stress and decreased with greater amounts of cross‐linking. The maximum strain actuation achieved was 296% under 100 kPa of bias stress, which resulted in work capacity of 296 kJ/m3 for the lowest cross‐linked networks. Overall, the experimental results provide a fundamental insight linking thermomechanical properties and actuation to a homogenous polydomain nematic LCE networks with order parameters of 0.80 when stretched. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 157–168

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“…The mesomorphic monomer M‐2 was synthesized according to our previously reported paper 31. White crystalline was obtained (mp: 135 °C, yield: 91%).…”

Section: Methodsmentioning

confidence: 99%

Synthesis and phase behavior of nematic liquid‐crystalline elastomers derived from smectic crosslinking agent

Jia

Zhang

et al. 2005

J of Applied Polymer Sci

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ABSTRACT:A mesogenic crosslinking agent M-1 was synthesized to minimize the perturbations of nonmesogenic crosslinking agent for liquid-crystalline elastomers. The synthesis of side-chain liquid-crystalline elastomers containing a rigid mesogenic crosslinking agent M-1 and a nematic monomer M-2 was described by a one-step hydrosilylation reaction. The chemical structures of the obtained monomers and network polymers were confirmed by Fourier transform infrared and 1 H-NMR spectroscopy. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction measurements. The influence of the crosslinking units on the phase behavior was discussed. The liquid-crystalline elastomers containing less than 15 mol % of the crosslinking units showed elasticity, reversible phase transition, and threaded texture. The experimental results demonstrated that isotropic temperature and liquid-crystalline range of polymers P-1-P-7 decreased a little as the concentration of crosslinking agent M-1 increased, and the use of mesomorphic crosslinking agent M-1 promotes the arrangement of liquid-crystalline units from P-1 to P-5.

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Synthesis and structure of polysiloxane liquid crystalline elastomers with a mesogenic crosslinking agent

Cited by 16 publications

References 30 publications

Liquid crystalline elastomers based on diglycidyl terminated rigid monomers and aliphatic acids. Part 1. Synthesis and characterization

Liquid crystalline elastomers based on diglycidyl terminated rigid monomers and aliphatic acids. Part 1. Synthesis and characterization

Thiol‐acrylate main‐chain liquid‐crystalline elastomers with tunable thermomechanical properties and actuation strain

Synthesis and phase behavior of nematic liquid‐crystalline elastomers derived from smectic crosslinking agent

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