Nowadays,the increasing electromagnetic waves generated by wearable devices are becoming an emerging issue for human health,so stretchable electromagnetic interference(EMI)shielding materials are highly demanded.Eleph...Nowadays,the increasing electromagnetic waves generated by wearable devices are becoming an emerging issue for human health,so stretchable electromagnetic interference(EMI)shielding materials are highly demanded.Elephant trunks are capable of grabbing fragile vegetation and tearing trees thanks not only to their muscles but also to their folded skins.Inspired by the wrinkled skin of the elephant trunks,herein,we propose a winkled conductive film based on single-walled carbon nanotubes(SWCNTs)for multifunctional EMI applications.The conductive film has a sandwich structure,which was prepared by coating SWCNTs on both sides of the stretched elastic latex cylindrical substrate.The shrinking-induced winkled conductive network could withstand up to 200%tensile strain.Typically,when the stretching direction is parallel to the polarization direction of the electric field,the total EMI shielding effectiveness could surprisingly increase from 38.4 to 52.7 dB at 200%tensile strain.It is mainly contributed by the increased connection of the SWCNTs.In addition,the film also has good Joule heating performance at several voltages,capable of releasing pains in injured joints.This unique property makes it possible for strain-adjustable multifunctional EMI shielding and wearable thermotherapy applications.展开更多
The surface wrinkling of biological tissues is ubiquitous in nature.Accumulating evidence suggests that the mechanical force plays a significant role in shaping the biological morphologies.Controlled wrinkling has bee...The surface wrinkling of biological tissues is ubiquitous in nature.Accumulating evidence suggests that the mechanical force plays a significant role in shaping the biological morphologies.Controlled wrinkling has been demonstrated to be able to spontaneously form rich multiscale patterns,on either planar or curved surfaces.The surface wrinkling on planar substrates has been investigated thoroughly during the past decades.However,most wrinkling morphologies in nature are based on the curved biological surfaces and the research of controllable patterning on curved substrates still remains weak.The study of wrinkling on curved substrates is critical for understanding the biological growth,developing threedimensional(3D)or four-dimensional(4D)fabrication techniques,and creating novel topographic patterns.In this review,fundamental wrinkling mechanics and recent advances in both fabrications and applications of the wrinkling patterns on curved substrates are summarized.The mechanics behind the wrinkles is compared between the planar and the curved cases.Beyond the film thickness,modulus ratio,and mismatch strain,the substrate curvature is one more significant parameter controlling the surface wrinkling.Curved substrates can be both solid and hollow with various 3D geometries across multiple length scales.Up to date,the wrinkling morphologies on solid/hollow core-shell spheres and cylinders have been simulated and selectively produced.Emerging applications of the curved topographic patterns have been found in smart wetting surfaces,cell culture interfaces,healthcare materials,and actuators,which may accelerate the development of artificial organs,stimuli-responsive devices,and micro/nano fabrications with higher dimensions.展开更多
Activation of silent synapses is of great significance for the extension of neural plasticity related to learning and memory.Inspired by the activation of silent synapses via receptor insertion in neural synapses,we p...Activation of silent synapses is of great significance for the extension of neural plasticity related to learning and memory.Inspired by the activation of silent synapses via receptor insertion in neural synapses,we propose an efficient method for activating artificial synapses through the intercalation of Sn in layered a-MoO_(3).Sn intercalation is capable of switching on the response of layered a-MoO_(3)to the stimuli of visible and near infrared light by decreasing the bandgap.This mimics the receptor insertion process in silent neural synapses.The Sn-intercalated MoO_(3)(Sn-MoO_(3))exhibits persistent photoconductivity due to the donor impurity induced by Sn intercalation.This enables the two-terminal Sn-MoO_(3)device promising optoelectronic synapse with an ultrahigh paired pulse facilitation(PPF)up to 199.5%.On-demand activation and tunable synaptic plasticity endow the device great potentials for extensible neuromorphic computing.Superior performance of the extensible artificial neural network(ANN)based on the Sn-MoO_(3)synapses are demonstrated in pattern recognition.Impressively,the recognition accuracy increases from 89.7%to 94.8%by activating more nodes into the ANN.This is consistent with the recognition process of physical neural network during brain development.The intercalation engineering of MoO_(3)may provide inspirations for the design of high-performance neuromorphic computing architectures.展开更多
基金financially supported by the National Natural Science Foundation of China(52073302,52103311)Hunan Provincial Natural Science Foundation for Distinguished Young Scholars(No.14JJ1001).
文摘Nowadays,the increasing electromagnetic waves generated by wearable devices are becoming an emerging issue for human health,so stretchable electromagnetic interference(EMI)shielding materials are highly demanded.Elephant trunks are capable of grabbing fragile vegetation and tearing trees thanks not only to their muscles but also to their folded skins.Inspired by the wrinkled skin of the elephant trunks,herein,we propose a winkled conductive film based on single-walled carbon nanotubes(SWCNTs)for multifunctional EMI applications.The conductive film has a sandwich structure,which was prepared by coating SWCNTs on both sides of the stretched elastic latex cylindrical substrate.The shrinking-induced winkled conductive network could withstand up to 200%tensile strain.Typically,when the stretching direction is parallel to the polarization direction of the electric field,the total EMI shielding effectiveness could surprisingly increase from 38.4 to 52.7 dB at 200%tensile strain.It is mainly contributed by the increased connection of the SWCNTs.In addition,the film also has good Joule heating performance at several voltages,capable of releasing pains in injured joints.This unique property makes it possible for strain-adjustable multifunctional EMI shielding and wearable thermotherapy applications.
基金financially supported by National Natural Science Foundation of China(Nos.61574172 and 31971291)Hunan Provincial Natural Science Foundation for Distinguished Young Scholars(No.14JJ1001).
文摘The surface wrinkling of biological tissues is ubiquitous in nature.Accumulating evidence suggests that the mechanical force plays a significant role in shaping the biological morphologies.Controlled wrinkling has been demonstrated to be able to spontaneously form rich multiscale patterns,on either planar or curved surfaces.The surface wrinkling on planar substrates has been investigated thoroughly during the past decades.However,most wrinkling morphologies in nature are based on the curved biological surfaces and the research of controllable patterning on curved substrates still remains weak.The study of wrinkling on curved substrates is critical for understanding the biological growth,developing threedimensional(3D)or four-dimensional(4D)fabrication techniques,and creating novel topographic patterns.In this review,fundamental wrinkling mechanics and recent advances in both fabrications and applications of the wrinkling patterns on curved substrates are summarized.The mechanics behind the wrinkles is compared between the planar and the curved cases.Beyond the film thickness,modulus ratio,and mismatch strain,the substrate curvature is one more significant parameter controlling the surface wrinkling.Curved substrates can be both solid and hollow with various 3D geometries across multiple length scales.Up to date,the wrinkling morphologies on solid/hollow core-shell spheres and cylinders have been simulated and selectively produced.Emerging applications of the curved topographic patterns have been found in smart wetting surfaces,cell culture interfaces,healthcare materials,and actuators,which may accelerate the development of artificial organs,stimuli-responsive devices,and micro/nano fabrications with higher dimensions.
基金National Natural Science Foundation of China(52103311,62075240)the Scientific Researches Foundation of National University of Defense Technology(ZK18-01-03)National Key Research and Development Program of China(2020YFB2205804).
文摘Activation of silent synapses is of great significance for the extension of neural plasticity related to learning and memory.Inspired by the activation of silent synapses via receptor insertion in neural synapses,we propose an efficient method for activating artificial synapses through the intercalation of Sn in layered a-MoO_(3).Sn intercalation is capable of switching on the response of layered a-MoO_(3)to the stimuli of visible and near infrared light by decreasing the bandgap.This mimics the receptor insertion process in silent neural synapses.The Sn-intercalated MoO_(3)(Sn-MoO_(3))exhibits persistent photoconductivity due to the donor impurity induced by Sn intercalation.This enables the two-terminal Sn-MoO_(3)device promising optoelectronic synapse with an ultrahigh paired pulse facilitation(PPF)up to 199.5%.On-demand activation and tunable synaptic plasticity endow the device great potentials for extensible neuromorphic computing.Superior performance of the extensible artificial neural network(ANN)based on the Sn-MoO_(3)synapses are demonstrated in pattern recognition.Impressively,the recognition accuracy increases from 89.7%to 94.8%by activating more nodes into the ANN.This is consistent with the recognition process of physical neural network during brain development.The intercalation engineering of MoO_(3)may provide inspirations for the design of high-performance neuromorphic computing architectures.
