| Water is one of the most abundant and important resources in the world and is a source of natural energy.With the continuous development of science and technology,the study of converting energy in water into other forms of energy has attracted more and more attention.This article mainly studies the preparation of graphene oxide(GO)film,chitosan-multiwalled carbon nanotubes(MWCNTs)composite film and chitosan fiber,and explores their application in moisture-responsive actuators.The specific results are as follows:(1)Moisture-responsive actuator based on homogeneous GO filmThe free-standing films were obtained by suction filtration of the GO dispersion,and the response of the film is studied when there is a humidity difference between the upper and lower surfaces.This actuator shows a highly sensitive and ultrafast response to the stimuli of moisture with a bending speed of about 30°s-1.It can convert the potential energy in moisture to mechanical work,and has been exploited to lift cargoes 8 times heavier than itself.(2)Moisture-responsive actuator based on chitosan filmComposite films were prepared by chitosan and MWCNTs,while the different responses to humidity and dry gas were studied.The water adsorption/desbrption elicits remarkable shape reconfiguration including reversible bending,helical twisting and continual flipping.The film can transport cargo up to 65 times its own weight when the composite film was applied to a moisture-responsive actuator.In addition,there are different output signals for wet and dry gases when it was applied to electronic devices.(3)Water-and moisture-responsive actuator based on chitosan fiberThe twisted chitosan fibers were prepared by wet-spinning and twisting.The untwisting and recovery response of the fiber driven by water and water vapor was studied.The result shows that the 2.0 mg twisted fiber was able to rotate 5.0 g of the object while untwisting,and it was also possible to lift 0.50 g cargo like a crane. |
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