Moisture‐Activated Torsional Graphene‐Fiber Motor

Cheng, Huhu; Hu, Yue; Zhao, Fei; Dong, Zelin; Wang, Yanhong; Chen, Nan; Zhang, Zhipan; Qu, Liangti

doi:10.1002/adma.201305708

Cited by 315 publications

(298 citation statements)

References 23 publications

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“…For instance, large-diameter, wax-filled yarns made from niobium nanowires have been demonstrated to torsionally actuate by up to 12°/mm when electrically heated (47). Similar to water-absorbing CNT yarns, Cheng et al used twisted graphene oxide fibers to absorb water, delivering up to 5,190 rpm during torsional actuation (48). More recently, CruzSilva et al demonstrated graphene-oxide fibers that can be twisted, knotted, and coiled (49), potentially opening the path to tensile actuation from graphene fibers.…”

Section: Emerging Types Of Twisted Musclesmentioning

confidence: 99%

New twist on artificial muscles

Haines¹,

Spinks

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

290

211

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Lightweight artificial muscle fibers that can match the large tensile stroke of natural muscles have been elusive. In particular, low stroke, limited cycle life, and inefficient energy conversion have combined with high cost and hysteretic performance to restrict practical use. In recent years, a new class of artificial muscles, based on highly twisted fibers, has emerged that can deliver more than 2,000 J/kg of specific work during muscle contraction, compared with just 40 J/kg for natural muscle. Thermally actuated muscles made from ordinary polymer fibers can deliver long-life, hysteresis-free tensile strokes of more than 30% and torsional actuation capable of spinning a paddle at speeds of more than 100,000 rpm. In this perspective, we explore the mechanisms and potential applications of present twisted fiber muscles and the future opportunities and challenges for developing twisted muscles having improved cycle rates, efficiencies, and functionality. We also demonstrate artificial muscle sewing threads and textiles and coiled structures that exhibit nearly unlimited actuation strokes. In addition to robotics and prosthetics, future applications include smart textiles that change breathability in response to temperature and moisture and window shutters that automatically open and close to conserve energy.

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Section: Emerging Types Of Twisted Musclesmentioning

confidence: 99%

New twist on artificial muscles

Haines¹,

Spinks

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

290

211

View full text Add to dashboard Cite

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“…However, both of the two types of sensors cannot be used as flexible sensors due to the complicated measurement systems and nonflexible active materials. In addition to the above, other types of humidity sensors based on the change of impedance, voltage, or strain, have been reported [164][165][166].…”

Section: Flexible Humidity Sensorsmentioning

confidence: 94%

Advanced carbon materials for flexible and wearable sensors

et al. 2017

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Flexible and wearable sensors have drawn extensive concern due to their wide potential applications in wearable electronics and intelligent robots. Flexible sensors with high sensitivity, good flexibility, and excellent stability are highly desirable for monitoring human biomedical signals, movements and the environment. The active materials and the device structures are the keys to achieve high performance. Carbon nanomaterials, including carbon nanotubes (CNTs), graphene, carbon black and carbon nanofibers, are one of the most commonly used active materials for the fabrication of high-performance flexible sensors due to their superior properties. Especially, CNTs and graphene can be assembled into various multi-scaled macroscopic structures, including one dimensional fibers, two dimensional films and three dimensional architectures, endowing the facile design of flexible sensors for wide practical applications. In addition, the hybrid structured carbon materials derived from natural bio-materials also showed a bright prospect for applications in flexible sensors. This review provides a comprehensive presentation of flexible and wearable sensors based on the above various carbon materials. Following a brief introduction of flexible sensors and carbon materials, the fundamentals of typical flexible sensors, such as strain sensors, pressure sensors, temperature sensors and humidity sensors, are presented. Then, the latest progress of flexible sensors based on carbon materials, including the fabrication processes, performance and applications, are summarized. Finally, the remaining major challenges of carbon-based flexible electronics are discussed and the future research directions are proposed. [56,57], have been used as the active components for the fabrication of flexible sensors. Among these materials, metal NPs can be used to fabricate flexible sensors with high sensitivity, but the sensing range and stretchability of these sensors are limited [58]. Besides, due to the limited chemical stability and reproducibility of metal nanowires, it is challenging to fabricate stable sensors using metal nanowires [10]. Similarly, conductive polymers with poor stability and conductivity are also difficult to be used for the fabrication of high-performance sensors [59]. In contrast, carbon materials are one of the most commonly investigated materials, especially CNTs and graphene (including graphene oxide (GO) and reduced graphene oxide (rGO)), due to their remarkable mechanical, electrical and thermal properties. To implement macroscopic applications, CNTs and graphene with superior properties in microscopic level should be converted into macroscopic functional assemblies, such as one dimensional (1D) fibers or yarns [60,61], two dimensional (2D) films or sheets [62,63], three dimensional (3D) architectures [64][65][66] (Fig. 1). The multi-scaled macroscopic carbon nanomaterials endow the flexible sensors with high sensitivity, excellent flexibility and good stability as well as desired configurations. Also, lo...

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“…(C) Kinematics of hygroresponsive actuators with perpendicular and oblique reinforcement [53] 它方向上的分子将发生膨胀. 样品的平行取向会引起材料在垂直方向的收缩或膨胀 [101] . …”

Section: (B)可形状转变的水mentioning

confidence: 99%

Research Progress of Solvent-based Smart Actuator Materials

Zhang¹,

Liu²,

Chen³

et al. 2018

Acta Chim. Sinica

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Recently, smart actuator materials have drawn widespread research attention due to their important applications in soft robots, artificial muscles, sensors, or micro hand device preparation. In nature, there are many examples of actuator materials. For example, sea cucumbers can alter the stiffness of their dermis within seconds to obtain survival advantages and the venus flytrap can close their leaves in a second for efficient prey capture. Pinecones and flowers respond to their environment by opening and closing with the relative humidity changes. Inspired by these natural creatures, synthetic polymer microactuators such as polymer hydrogels and polymer composites are widely developed due to their important applications based on their response to external stimuli, such as light, heat, electronic, magnetic, solvent and humidity. In this work, we review the research progress of solvent-based smart actuator materials. There are mainly two kinds of solvent-actuator based on the fabrication method and actuator mechanism: one is a two-layer structure membrane formed by active layers-support layers with different expansion coefficients. The active layer is volumetrically expanded under the action of a solvent, and the support layer is a passive holder. The other is made of rigid material skeleton with a flexible material to make a single-layer composite membrane filler. The ionic gradient or the pore structure gradient of the material itself gives rise to the directional driving behavior with a varying solvent binding gradient. Otherwise, the membrane's bending drive behavior has been achieved by inducing a single material to form an infiltration gradient by a solvent infiltration process. Solvent-based smart actuator materials are prepared by introducing moisture or solvent-responsive molecules in a polymeric material to form a bilayers or monolayer structure. The material is distorted by volume deformation due to humidity or solvent field action. At present, a great deal of research work has been devoted to converting the mechanical deformation of solvent-based smart actuator materials into electric energy and developing related intelligent application in energy transformation, liquid switching, biomimicry, transportation of liquids and smart sensing. The paper presents a pioneering outlook for the further development of the solvent actuator materials.

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Moisture‐Activated Torsional Graphene‐Fiber Motor

Cited by 315 publications

References 23 publications

New twist on artificial muscles

New twist on artificial muscles

Advanced carbon materials for flexible and wearable sensors

Research Progress of Solvent-based Smart Actuator Materials

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