Modeling the polydomain-monodomain transition of liquid crystal elastomers

Whitmer, Jonathan K.; Roberts, Tyler F.; Shekhar, Raj; Abbott, Nicholas L.; Pablo, Juan

doi:10.1103/physreve.87.020502

Cited by 24 publications

(28 citation statements)

References 45 publications

(37 reference statements)

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“…These errors are added in the computation of the length and only a trend can be obtained. Similarly to previous studies [10][11][12][13], this trend, when extrapolated to equilibrium, i.e. infinitely small strain rates, shows that no transition region could be detected and the PM transition did not exhibit strain-softening but rather continued strain hardening.…”

Section: Viscoelasticity Of the Pm Transitionsupporting

confidence: 86%

“…For polydomain LCEs with nematic genesis, the PM transition does not result in a soft elasticity plateau and the stress response does not exhibit the 3 regions. The PM transition under equilibrium conditions gradually proceeds over a range of stress with no apparent plateau or soft elasticity [10][11][12][13]. However, away from equilibrium conditions, i.e.…”

Section: Introductionmentioning

confidence: 99%

“…In both studies [10,18], the range of strain rates explored was limited to relatively low values, with a maximum at 0.03%/s and 0.046%/s, respectively. In addition, the transition stress was either independent of strain rate [1,13] or increased with the strain rate [10].…”

Section: Introductionmentioning

confidence: 99%

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Viscoelasticity of the polydomain-monodomain transition in main-chain liquid crystal elastomers

Azoug

Vasconcellos

Dooling

et al. 2016

Polymer

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The goal of this study was to explore the rate-dependent behavior of the stretch-induced polydomainmonodomain (PM) transition of a liquid crystal elastomer (LCE). The main-chain LCE was synthesized and then cross-linked in the nematic polydomain state. The PM transition caused a soft-elastic behavior, which was measured using uniaxial tensile tests at multiple strain rates and temperatures. The main finding was that we were able to apply the temperature-dependent shift factor determined for the small strain behavior and in the frequency domain to create master curves for the large-strain response in the strain rate domain. The soft elasticity phenomenon was absent from the stress-strain curve at equilibrium. The results also suggest that the relaxation mechanisms of the network, and not of the mesogen orientation, dominate the rate-dependent behavior. Finally, we observed a relatively slow recovery behavior, suggesting the presence of an additional slow relaxation mechanism.

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Section: Viscoelasticity Of the Pm Transitionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

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Viscoelasticity of the polydomain-monodomain transition in main-chain liquid crystal elastomers

Azoug

Vasconcellos

Dooling

et al. 2016

Polymer

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“…While in this review we focus on aligned LCEs that undergo a reversible change in order on heating, it should be noted that unaligned, polydomain liquid crystal elastomers exhibit a number of intriguing properties. Extensive research has been carried on polydomain nematic elastomers (PNE) and polydomain smectic elastomers, regarding the polydomain to monodomain transition, the dynamics of relaxation processes, and the reversible actuation of these materials under load. These polydomain LCEs can be designed to retain strain, as such these have the potential to be used as shape memory materials capable of irreversible shape change …”

Section: Introductionmentioning

confidence: 99%

Liquid crystal elastomer actuators: Synthesis, alignment, and applications

Kularatne

Kim

Boothby

et al. 2017

J Polym Sci B Polym Phys

273

225

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Liquid crystal elastomers (LCEs) are a unique class of materials which combine rubber elasticity with the orientational order of liquid crystals. This combination can lead to materials with unique properties such as thermal actuation, anisotropic swelling, and soft elasticity. As such, LCEs are a promising class of materials for applications requiring stimulus response. These unique features and the recent developments of the LCE chemistry and processing will be discussed in this review. First, we emphasize several different synthetic pathways in conjunction with the alignment techniques utilized to obtain monodomain LCEs. We then identify the synthesis and alignment techniques used to synthesis LCE-based composites. Finally, we discuss how these materials are used as actuators and sensors.

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“…Therefore, to attack this critical problem and predict physical properties of LCPs, simulational studies from molecular point of view should be introduced. Molecular models and simulations for LCPs have been developed and performed over ten years [ 14 , 15 , 16 , 17 ].…”

Section: Introductionmentioning

confidence: 99%

Development of Coarse-Grained Liquid-Crystal Polymer Model with Efficient Electrostatic Interaction: Toward Molecular Dynamics Simulations of Electroactive Materials

et al. 2018

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Liquid-crystal polymers (LCPs) are well known materials for functional sensor and actuators, because of their high-responsiveness to an electric field. Owing to their complex physical nature, however, the prediction of the functions of LCPs is a challenge. To attack this problem from a molecular point of view, a simulation study is a promising approach. In this work, for future applications of molecular dynamics simulations to problems involving an electric field, we develop an LCP model which consists of coarse-grained mesogenic molecules and smeared charges. For the smearing function of the electrostatic force, the Gauss error function is introduced. This smearing is optimized to attain a reasonable accuracy for phase transition phenomena of liquid crystal while numerical instabilities arising from the singularity of the Coulomb potential are circumvented. For swelling systems, our LCP model exhibits the characteristics of both liquid crystals and unentangled polymer chains; orientational order of the mesogenic units and Rouse-like relaxation dynamics. Our coarse-grained LCP model successfully incorporates electric charges and dipoles and is therefore applicable to problems concerning an electric field.

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Modeling the polydomain-monodomain transition of liquid crystal elastomers

Cited by 24 publications

References 45 publications

Viscoelasticity of the polydomain-monodomain transition in main-chain liquid crystal elastomers

Viscoelasticity of the polydomain-monodomain transition in main-chain liquid crystal elastomers

Liquid crystal elastomer actuators: Synthesis, alignment, and applications

Development of Coarse-Grained Liquid-Crystal Polymer Model with Efficient Electrostatic Interaction: Toward Molecular Dynamics Simulations of Electroactive Materials

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