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A multi-responsive water-driven actuator with instant and powerful performance for versatile applications.

Mu J, Hou C, Zhu B, Wang H, Li Y, Zhang Q - Sci Rep (2015)

Bottom Line: Mechanical actuators driven by water that respond to multiple stimuli, exhibit fast responses and large deformations, and generate high stress have potential in artificial muscles, motors, and generators.Meeting all these requirements in a single device remains a challenge.The graphene monolayer paper has potential in artificial muscles, robotic hands, and electromagnetic-free generators.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, 201620 (People's Republic of China).

ABSTRACT
Mechanical actuators driven by water that respond to multiple stimuli, exhibit fast responses and large deformations, and generate high stress have potential in artificial muscles, motors, and generators. Meeting all these requirements in a single device remains a challenge. We report a graphene monolayer paper that undergoes reversible deformation. Its graphene oxide cells wrinkle and extend in response to water desorption and absorption, respectively. Its fast (~0.3 s), powerful (>100 MPa output stress, 7.5 × 10(5) N kg(-1) unit mass force), and controllable actuation can be triggered by moisture, heat, and light. The graphene monolayer paper has potential in artificial muscles, robotic hands, and electromagnetic-free generators.

No MeSH data available.


Related in: MedlinePlus

Thermal-responsive behaviour of the GM paper and its locomotion in response to moisture and heat.(a) ATR-IR spectra of the GM paper measured at different temperatures. (b) Time-dependent weight measurements of the paper under on/off heating. Insets show the paper (20 × 30 mm) deformation. It was heated for 20 s and then allowed to cool to room temperature. (c) Representative images and schematics of the paper's multistage locomotion.
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f4: Thermal-responsive behaviour of the GM paper and its locomotion in response to moisture and heat.(a) ATR-IR spectra of the GM paper measured at different temperatures. (b) Time-dependent weight measurements of the paper under on/off heating. Insets show the paper (20 × 30 mm) deformation. It was heated for 20 s and then allowed to cool to room temperature. (c) Representative images and schematics of the paper's multistage locomotion.

Mentions: Temperature is a more effective trigger than moisture for the current actuator. Attenuated total reflectance-infrared (ATR-IR) spectra (Fig. 4a) of the GM paper show that the intensity of the hydroxyl stretching vibration of water decreases with increasing temperature. Fig. 4b shows the GM paper rapidly loses up to 20% of water by weight, as the temperature increases to 55°C. It gradually absorbs up to 20% water by initial weight, upon cooling to room temperature in humid air. Therefore, we further investigate the water molecule content-dependent bending angle of the actuator. The specific water molecule number change (ΔSN, Note S2) and the bending angle show near-linear dependency (Fig. S5). Conventional rGO paper exhibits negligible weight changes and deformation during the same test. This suggests that only the GO regions of the rGO/GO structured paper are responsible for actuation. A small change in surface temperature (~4°C from 0 to 1 s; ~1°C from 20 to 21 s) results in significant deformation of the actuator (Fig. 4b inset). This could be attributed to water being easily removed from the GO surface26, and free water easily transferring into cellular channels. The asymmetric response of the two faces enables the rGO/GO monolayer paper to exhibit a rapid, well-controlled and continuous motion in a pre-established manner. The GM paper can spontaneously and continuously flip and navigate over a vapour-heated filter membrane, when triggered by both moisture and heat (Movie S1 and Fig. 4c). A typical cycle occurs in two stages: 1) When the rGO region faces down, the GM paper resists water vapour but conducts heat. The GO region is thus heated and contracts, causing the GM paper to curl away from the substrate (Fig. 4c I–III); 2) once the paper flips and the GO region faces down, there exist two deformation mechanisms—the dominant moisture-induced swelling of GO, and the secondary thermal-induced deswelling of GO. The swelling effect is much stronger, so that the paper begins to uncurl (Fig. 4c IV) and then curl in the opposite direction. The paper then flips again, so that the rGO region faces down (Fig. 4c V–VIII), and a new cycle begins.


A multi-responsive water-driven actuator with instant and powerful performance for versatile applications.

Mu J, Hou C, Zhu B, Wang H, Li Y, Zhang Q - Sci Rep (2015)

Thermal-responsive behaviour of the GM paper and its locomotion in response to moisture and heat.(a) ATR-IR spectra of the GM paper measured at different temperatures. (b) Time-dependent weight measurements of the paper under on/off heating. Insets show the paper (20 × 30 mm) deformation. It was heated for 20 s and then allowed to cool to room temperature. (c) Representative images and schematics of the paper's multistage locomotion.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4379955&req=5

f4: Thermal-responsive behaviour of the GM paper and its locomotion in response to moisture and heat.(a) ATR-IR spectra of the GM paper measured at different temperatures. (b) Time-dependent weight measurements of the paper under on/off heating. Insets show the paper (20 × 30 mm) deformation. It was heated for 20 s and then allowed to cool to room temperature. (c) Representative images and schematics of the paper's multistage locomotion.
Mentions: Temperature is a more effective trigger than moisture for the current actuator. Attenuated total reflectance-infrared (ATR-IR) spectra (Fig. 4a) of the GM paper show that the intensity of the hydroxyl stretching vibration of water decreases with increasing temperature. Fig. 4b shows the GM paper rapidly loses up to 20% of water by weight, as the temperature increases to 55°C. It gradually absorbs up to 20% water by initial weight, upon cooling to room temperature in humid air. Therefore, we further investigate the water molecule content-dependent bending angle of the actuator. The specific water molecule number change (ΔSN, Note S2) and the bending angle show near-linear dependency (Fig. S5). Conventional rGO paper exhibits negligible weight changes and deformation during the same test. This suggests that only the GO regions of the rGO/GO structured paper are responsible for actuation. A small change in surface temperature (~4°C from 0 to 1 s; ~1°C from 20 to 21 s) results in significant deformation of the actuator (Fig. 4b inset). This could be attributed to water being easily removed from the GO surface26, and free water easily transferring into cellular channels. The asymmetric response of the two faces enables the rGO/GO monolayer paper to exhibit a rapid, well-controlled and continuous motion in a pre-established manner. The GM paper can spontaneously and continuously flip and navigate over a vapour-heated filter membrane, when triggered by both moisture and heat (Movie S1 and Fig. 4c). A typical cycle occurs in two stages: 1) When the rGO region faces down, the GM paper resists water vapour but conducts heat. The GO region is thus heated and contracts, causing the GM paper to curl away from the substrate (Fig. 4c I–III); 2) once the paper flips and the GO region faces down, there exist two deformation mechanisms—the dominant moisture-induced swelling of GO, and the secondary thermal-induced deswelling of GO. The swelling effect is much stronger, so that the paper begins to uncurl (Fig. 4c IV) and then curl in the opposite direction. The paper then flips again, so that the rGO region faces down (Fig. 4c V–VIII), and a new cycle begins.

Bottom Line: Mechanical actuators driven by water that respond to multiple stimuli, exhibit fast responses and large deformations, and generate high stress have potential in artificial muscles, motors, and generators.Meeting all these requirements in a single device remains a challenge.The graphene monolayer paper has potential in artificial muscles, robotic hands, and electromagnetic-free generators.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, 201620 (People's Republic of China).

ABSTRACT
Mechanical actuators driven by water that respond to multiple stimuli, exhibit fast responses and large deformations, and generate high stress have potential in artificial muscles, motors, and generators. Meeting all these requirements in a single device remains a challenge. We report a graphene monolayer paper that undergoes reversible deformation. Its graphene oxide cells wrinkle and extend in response to water desorption and absorption, respectively. Its fast (~0.3 s), powerful (>100 MPa output stress, 7.5 × 10(5) N kg(-1) unit mass force), and controllable actuation can be triggered by moisture, heat, and light. The graphene monolayer paper has potential in artificial muscles, robotic hands, and electromagnetic-free generators.

No MeSH data available.


Related in: MedlinePlus