Measurement of electrically induced shear strain in a chiral smectic liquid-crystal elastomer

Na, Yang Ho; Aburaya, Yuki; Orihara, Hiroshi; Hiraoka, Kazuyuki

doi:10.1103/physreve.83.061709

Cited by 37 publications

(21 citation statements)

References 29 publications

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“…To achieve contraction of the LCE, the film needs to be thin and the material needs to be exposed to light over a long time period (of the order of minutes to hours) in order to accumulate enough light energy [23,34]. An alternative LCE modification involves the incorporation of ferroelectric mesogens (having a high dielectric anisotropy) in order to sensitize the LCEs to an electric field [35][36][37]. These mesogens in side-chain LCEs can change their alignment in response to an external electric field, resulting in an electromechanical effect with response times that can be of the order of 10 ms.…”

Section: Open Accessmentioning

confidence: 99%

Nanoparticle-Liquid Crystalline Elastomer Composites

Marshall

Terentjev

2012

Polymers

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Liquid crystalline elastomers (LCEs) exhibit a number of remarkable physical effects, including a uniquely high-stroke reversible mechanical actuation triggered by external stimuli. Fundamentally, all such stimuli affect the degree of liquid crystalline order in the polymer chains cross-linked into an elastic network. Heat and the resulting thermal actuation act by promoting entropic disorder, as does the addition of solvents. Photo-isomerization is another mechanism of actuation, reducing the orientational order by diminishing the fraction of active rod-like mesogenic units, mostly studied for azobenzene derivatives incorporated into the LCE composition. Embedding nanoparticles provides a new, promising strategy to add functionality to LCEs and ultimately enhance their performance as sensors and actuators. The motivation for the combination of nanoparticles with LCEs is to provide better-controlled actuation stimuli, such as electric and magnetic fields, and broad-spectrum light, by selecting and configuring the appropriate nanoparticles in the LCE matrix. Here we give an overview of recent advances in this area with a focus on preparation, physical properties and actuation performance of the resultant nanocomposites.

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Section: Open Accessmentioning

confidence: 99%

Nanoparticle-Liquid Crystalline Elastomer Composites

Marshall

Terentjev

2012

Polymers

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“…When ferroelectric LCs are chemically bound to a soft polymer network, forming an LCE as described above, the material can undergo contraction when exposed to an external electric field [ 23 , 177 , 178 ]; the strain changes reported were rather low, approximately 4% in response to applied fields of the order of 1 MVm −1 [ 23 ]. These materials also tend to be rather soft (with an elastic modulus of the order of MPa), so that, although the applied field causes a strain change, the material is not capable of exerting a large force.…”

Section: Electronic Electroactive Polymers For Sensingmentioning

confidence: 99%

Electroactive polymers for sensing

et al. 2016

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Electromechanical coupling in electroactive polymers (EAPs) has been widely applied for actuation and is also being increasingly investigated for sensing chemical and mechanical stimuli. EAPs are a unique class of materials, with low-moduli high-strain capabilities and the ability to conform to surfaces of different shapes. These features make them attractive for applications such as wearable sensors and interfacing with soft tissues. Here, we review the major types of EAPs and their sensing mechanisms. These are divided into two classes depending on the main type of charge carrier: ionic EAPs (such as conducting polymers and ionic polymer–metal composites) and electronic EAPs (such as dielectric elastomers, liquid-crystal polymers and piezoelectric polymers). This review is intended to serve as an introduction to the mechanisms of these materials and as a first step in material selection for both researchers and designers of flexible/bendable devices, biocompatible sensors or even robotic tactile sensing units.

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“…LCEs are advanced multifunctional materials that combine the flexibility of polymeric networks with the nematic structure of liquid crystals [41,42], which have the advantages of having a fast response, recoverable deformation, and low noise [10,[43][44][45]. This special composition and structure enable LCEs to respond to external light [46][47][48][49], heat [50], electric fields [51,52], magnetic fields [53] and chemical substances [54]. Based on LCE materials, several self-exciting motion modes have been constructed, such as rolling [20], vibration [17], swinging [10,55], stretching and shrinking [56], rotation [57], eversion or inversion [9,58], torsion [59], jumping [60], and buckling [61] modes.…”

Section: Introductionmentioning

confidence: 99%

Self-Sustained Collective Motion of Two Joint Liquid Crystal Elastomer Spring Oscillator Powered by Steady Illumination

Cheng

et al. 2022

Micromachines

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For complex micro-active machines or micro-robotics, it is crucial to clarify the coupling and collective motion of their multiple self-oscillators. In this article, we construct two joint liquid crystal elastomer (LCE) spring oscillators connected by a spring and theoretically investigate their collective motion based on a well-established dynamic LCE model. The numerical calculations show that the coupled system has three steady synchronization modes: in-phase mode, anti-phase mode, and non-phase-locked mode, and the in-phase mode is more easily achieved than the anti-phase mode and the non-phase-locked mode. Meanwhile, the self-excited oscillation mechanism is elucidated by the competition between network that is achieved by the driving force and the damping dissipation. Furthermore, the phase diagram of three steady synchronization modes under different coupling stiffness and different initial states is given. The effects of several key physical quantities on the amplitude and frequency of the three synchronization modes are studied in detail, and the equivalent systems of in-phase mode and anti-phase mode are proposed. The study of the coupled LCE spring oscillators will deepen people’s understanding of collective motion and has potential applications in the fields of micro-active machines and micro-robots with multiple coupled self-oscillators.

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Measurement of electrically induced shear strain in a chiral smectic liquid-crystal elastomer

Cited by 37 publications

References 29 publications

Nanoparticle-Liquid Crystalline Elastomer Composites

Nanoparticle-Liquid Crystalline Elastomer Composites

Electroactive polymers for sensing

Self-Sustained Collective Motion of Two Joint Liquid Crystal Elastomer Spring Oscillator Powered by Steady Illumination

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