Liquid Crystal Elastomer Actuators from Anisotropic Porous Polymer Template

Wang, Qian; Yu, Li; Yu, Meina; Zhao, Dongyu; Song, Ping; Chi, Hun; Guo, Lin; Yang, Huai

doi:10.1002/marc.201600699

Cited by 21 publications

(17 citation statements)

References 39 publications

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“…However, recent developments in LCE synthetic chemistry have allowed these obstacles to be overcome, for example, the photo-crosslinking of functionalised main-chain polyesters [25], photopolymerisation of acrylates [10], cross-linking of functionalised liquid crystal polymers [10], and hydrosilyation reactions [26]. More recently "click reactions" have been used for LCE synthesis [11,19,27,28]. "Click chemistry" is a term that was introduced by K. B. Sharpless in 2001 to describe reactions that are high yielding, wide in scope, stereospecific, simple to preform, create only by-products that can be removed without chromatography, and can be conducted in easily removable or benign solvents [29].…”

Section: Background To Liquid Crystal Elastomers and Liquid Crystalsmentioning

confidence: 99%

“…There are extensive techniques that have been explored for LCE monodomain alignment. Some of these include: mechanical rubbing [28,33], magnetic [13,34], and electric fields [35,36], photoalignment [37,38], and stress alignment [39,40]. More recently, however, advanced alignment techniques have been explored.…”

Section: Background To Liquid Crystal Elastomers and Liquid Crystalsmentioning

confidence: 99%

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Liquid Crystal Elastomers for Biological Applications

et al. 2021

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The term liquid crystal elastomer (LCE) describes a class of materials that combine the elastic entropy behaviour associated with conventional elastomers with the stimuli responsive properties of anisotropic liquid crystals. LCEs consequently exhibit attributes of both elastomers and liquid crystals, but additionally have unique properties not found in either. Recent developments in LCE synthesis, as well as the understanding of the behaviour of liquid crystal elastomers—namely their mechanical, optical and responsive properties—is of significant relevance to biology and biomedicine. LCEs are abundant in nature, highlighting the potential use of LCEs in biomimetics. Their exceptional tensile properties and biocompatibility have led to research exploring their applications in artificial tissue, biological sensors and cell scaffolds by exploiting their actuation and shock absorption properties. There has also been significant recent interest in using LCEs as a model for morphogenesis. This review provides an overview of some aspects of LCEs which are of relevance in different branches of biology and biomedicine, as well as discussing how recent LCE advances could impact future applications.

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Section: Background To Liquid Crystal Elastomers and Liquid Crystalsmentioning

confidence: 99%

Section: Background To Liquid Crystal Elastomers and Liquid Crystalsmentioning

confidence: 99%

Liquid Crystal Elastomers for Biological Applications

et al. 2021

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“…The direction of microchannels [83] p [83] The size of microchannels [83] Figure 3C Alignment template from anisotropic porous materials The stretching direction of anisotropic pores [86] Â The porous density of alignment templates…”

Section: Alignment Template Prepared By Rubbingmentioning

confidence: 99%

Varied Alignment Methods and Versatile Actuations for Liquid Crystal Elastomers: A Review

Zhao

Zhang

2021

Advanced Intelligent Systems

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Liquid crystal elastomers (LCEs) are a class of polymer materials that can produce reversible strain responses under heat, [1,2] light, [3][4][5][6] electric field [7] (or electric induction heat), [8,9] magnetic field (or magnetic induction heat), [10,11] moisture, [12] or solvent, [13] etc. They have attracted intense attention due to their enormous potential applications in soft robots, [1,9,[14][15][16][17][18] soft actuators, [4,8,14,[19][20][21][22][23] sensors, [22,[24][25][26] artificial muscles, [27][28][29] biomedicine, [30,31] flexible electronics, [32,33] light energy collection, [34] etc.LCEs are composed of rigid mesogens and flexible polymer networks, with the result that the anisotropy of liquid crystal and the rubber elasticity of polymer network can be both shown in LCEs. [35][36][37] Induced by mechanical stress, external field, or surface effect, the long axes of the mesogens can be aligned into specific directions (expressed by the director n), and this process is called alignment. Liquid crystal polymers after alignment are chemically [38] or physically [39] crosslinked to form anisotropic monodomain (including nematic, smectic, or cholesteric) LCEs. On the contrary, LCEs are in a polydomain state with isotropy when the directors of liquid crystal domains are arranged disorderly. Triggered by the external physical or chemical stimuli, the response and deformation originated from the phase transition from a liquid crystalline phase to an isotropic phase is significantly enhanced in the monodomain LCEs. This process is macroscopically manifested as the size shrinkage of LCEs in the orientation direction. [40,41] Therefore, the orientation degree of LCEs affects the maximum deformation actuated by the external stimuli to a large extent, whereas the orientation direction of LCEs determines their macroscopic deformation direction. The programmability of the mesogen orientation lays a foundation for achieving versatile deformation actuations of LCEs. [42] Aligning the mesogen orientation and achieving versatile actuations of LCEs are always the central research objects in the field of LCEs, and have developed rapidly in recent years. However, few reviews are addressing these two important issues simultaneously.Herein, in Section 1, we briefly elucidate the relationships between the microscopic orientation structure of LCEs, external stimuli, and macroscopic deformation characteristics of LCEs. In Section 2, we introduce three types of LCE alignment methods and their basic principles, and focus on comparing their programmability toward the mesogen orientation. In Section 3, we summarize two types of actuations for LCEs on the basis of the latest development, and focus on comparing their deformation controllability. In Section 4, we propose an outlook for the future key technologies to develop versatile, precise, and fastresponsive deformation actuations for LCEs. This review aims to help people to design and prepare LCEs with programmable orientation structure and excellent actuation characteristic...

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“…developed a template method for alignment of mesogens which can prevent dust and electrostatic charge that is generated during the mechanical rubbing process of alignment surface fabrication. [ 161 ] A thermal‐responsive bending bilayer structure with elongated elliptical pores that are filled with aligned mesogens was fabricated by this template method ( Figure a).…”

Section: Stimuli‐responsive Lcpsmentioning

confidence: 99%

Section: Stimuli‐responsive Lcpsmentioning

confidence: 99%

Smart Polymers for Microscale Machines

Tan

Davis

Cappelleri

2020

Adv Funct Materials

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Microscale machines are able to perform a number of tasks like micromanipulation, drug‐delivery, and noninvasive surgery. In particular, microscale polymer machines that can perform intelligent work for manipulation or transport, adaptive locomotion, or sensing are in‐demand. To achieve this goal, shape‐morphing smart polymers like hydrogels, liquid crystalline polymers, and other smart polymers are of great interest. Structures fabricated by these materials undergo mechanical motion under stimulation such as temperature, pH, light, and so on. The use of these materials renders microscale machines that undergo complex stimuli‐responsive transformation such as from planar to 3D by combining spatial design like introducing in‐plane or out‐plane differences. During the past decade, many techniques have been developed or adopted for fabricating structures with smart polymers including microfabrication methods and the well‐known milestone of 4D printing, starting in 2013. In this review, the existing or potential active smart polymers that could be used to fabricate active microscale machines to accomplish complex tasks are summarized.

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Liquid Crystal Elastomer Actuators from Anisotropic Porous Polymer Template

Cited by 21 publications

References 39 publications

Liquid Crystal Elastomers for Biological Applications

Liquid Crystal Elastomers for Biological Applications

Varied Alignment Methods and Versatile Actuations for Liquid Crystal Elastomers: A Review

Smart Polymers for Microscale Machines

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