A bio-inspired homogeneous graphene oxide actuator driven by moisture gradients

Ge, Yuanhang; Cao, Rui; S, Ye; Chen, Ze; Zhu, Zhifeng; Tu, Yingfeng; Ge, Dengteng; Yang, Xiaoming

doi:10.1039/c8cc00394g

Cited by 90 publications

(96 citation statements)

References 24 publications

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“…GO and CNa showed maximum bending angles of 13° and 34°, respectively. The value observed for GO was lower with respect to the data reported in literature, due to the lower operating temperature and to the larger thickness of our films. Increasing contents of CNa in the hybrid systems induced a remarkable increase of bending, as CNa/GO 20/80 and CNa/GO 40/60 showed bending angles of about 40° and 35°, respectively.…”

Section: Resultscontrasting

confidence: 87%

“…Qualitative assessments of the bending capability of GO, CNa, and hybrid films indicated that all of them quickly deflected upward (within seconds) once placed on a bare palm, whereas they did not bend when placed on dry substrates. The bending is well explained by a difference of relative humidity between the two sides of the film, which generates a bilayer‐like structure in terms of moisture gradient induced in the direction perpendicular to the film surfaces . A schematic representation of this phenomenon is depicted in Figure a, where a hybrid film section is constituted by orange and black rectangles, representing respectively CNa and GO platelets.…”

Section: Resultsmentioning

confidence: 99%

“…Nevertheless, producing multilayer structures is not the only possible approach for the realization of humidity‐driven reversible actuators. Indeed, very recently, reversible bending induced by moisture has been observed in GO films obtained by vacuum filtration as well as in monocomponent cellulose nanofiber films . For both these systems, the formation of a bilayer‐like structure of the film, obtained by anisotropic exposure to water vapor, is responsible for their bending.…”

Section: Introductionmentioning

confidence: 99%

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Humidity‐Driven Mechanical and Electrical Response of Graphene/Cloisite Hybrid Films

Castaldo

Lama

Aprea

et al. 2018

Adv Funct Materials

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Humidity-driven and electrically responsive graphene/cloisite hybrid films are obtained by casting water dispersions of graphene oxide and cloisite Na + . Coupling hydrophilicity and a high water vapor barrier in a homogenous film enables to realize humidity-driven actuators which exploit the water gradient generated across the film section under asymmetric exposure to humidity. The hybrid films are self-standing, flexible, and exhibit fast humidity-triggered bidirectional bending up to 75°, which is tuned by varying the relative amount of the two components. Up to 60% of the bending angle can be preserved at the steady state, providing a large and reliable response to humidity. Moreover, thermal treatment results in the reduction of graphene oxide, endowing the films with humidity-dependent electrical conductivity, which increases from 1.5 × 10 −6 S at 20% relative humidity (RH) up to 2.7 × 10 −5 S at 90% RH. The films are used to realize a humiditysensitive electrical switching system in which the reversible actuation is due to water desorption induced by the Joule effect. Due to their ease of preparation and tunable properties, this new class of graphene-based materials is suitable for the realization of humidity-driven and electrically responsive actuators and sensors. development of new humidity-driven mechanically and electrically responsive actuators and sensors.

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Section: Resultscontrasting

confidence: 87%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Humidity‐Driven Mechanical and Electrical Response of Graphene/Cloisite Hybrid Films

Castaldo

Lama

Aprea

et al. 2018

Adv Funct Materials

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“…Recently, our group reported an actuator driven by the moisture gradients of a homogeneous graphene oxide (GO) film, due to the in situ formation of a bilayer structure caused by water adsorption (Figure ). This actuator displays fast and controllable bending motions, along with the ability to lift objects eight times heavier than its own weight . Because the materials are largely abundant and cost effective, humidity actuators will open the path to more abilities in smart textiles and soft robotics.…”

Section: Actuation Mechanismsmentioning

confidence: 99%

Flexible Actuators for Soft Robotics

Yang

et al. 2019

Advanced Intelligent Systems

Self Cite

105

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Rigid robots have taken on a variety of automated manufacturing tasks and have made a huge contribution to industrial development; however, they are not suitable for further wearable applications due to their rigid and bulky structure, poor environmental adaptability, and low safety. Soft robots, which are mainly fabricated with flexible or elastomeric materials, can easily adjust to environmental changes and accomplish complex tasks, offering a new paradigm to achieve human-machine compliance. Soft robots do not replace rigid robots but add diverse features for softer robotic applications. In particular, the use of flexible actuators in robotic systems can realize certain intelligent functions, enrich soft robotic systems and migrate academic research to engineering applications. Currently, the application of flexible actuators in soft robotic fields is still at the embryonic stage. However, tremendous application spaces can be envisaged when combining flexible actuators with soft wearable robotics. Therefore, the current flexible actuators that rely on different external stimuli are addressed herein, and their materials, designs, and approaches suitable for soft robotic applications are highlighted. The application advancement and future perspective of flexible actuator prototypes toward various soft robotics are also discussed.

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“…In recent years, the demand for smart actuators based on flexible intelligent driving materials has increased [1][2][3][4]. The role of flexible intelligent driving materials is to convert external stimuli (such as light, heat, humidity, magnetic field/electric field) into executable actions or signals needed by processors through rapid, reversible and controllable structural/morphological changes [5][6][7][8][9][10][11][12][13][14][15][16]. Flexible smart actuators driven by these stimuli have significant advantages in the soft robot, electronic skin, bionic technology and other fields [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Smart Devices Based on the Soft Actuator with Nafion-Polypropylene-PDMS/Graphite Multilayer Structure

Wei

Zhang

et al. 2020

Applied Sciences

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Featured Application: This stimulus-driven, fast-response and large-scale deformation flexible actuator provides a new alternative for bionic application, artificial skin, and soft sensor development. Abstract:The demand for multi-functional soft actuators with simple fabrication and fast response to multiple stimuli is increasing in the field of smart devices. However, for existing actuators that respond to a single stimulus, it is difficult to meet the requirements of application diversity. Herein, a type of multi-stimulus responsive soft actuator based on the Nafion-Polypropylene-polydimethylsiloxane (PDMS)/Graphite multilayer membranes is proposed. Such actuators have an excellent reversible response to optical/thermal and humidity stimulation, which can reach a 224.56 • bending angle in a relative humidity of 95% within 5 s and a maximum bending angle of 324.65 • in 31 s when the platform temperature is 80 • C, and has a faster response (<0.5 s) to optical stimuli, as an asymmetric structure allows it to bend in both directions. Based on such an actuator, some applications like flexible grippers and switches to carry items or control circuits, bionic flytraps to capture and release "prey", have also been developed and studied. These provide potential applications in the fields of soft sensors, artificial skin and flexible robots.

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A bio-inspired homogeneous graphene oxide actuator driven by moisture gradients

Cited by 90 publications

References 24 publications

Humidity‐Driven Mechanical and Electrical Response of Graphene/Cloisite Hybrid Films

Humidity‐Driven Mechanical and Electrical Response of Graphene/Cloisite Hybrid Films

Flexible Actuators for Soft Robotics

Smart Devices Based on the Soft Actuator with Nafion-Polypropylene-PDMS/Graphite Multilayer Structure

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