| In recent years,a growing number of researchers have focused on self-powered and deformable flexible sensors.There are scattered mechanical energy in our surrounding environment,including mechanical energy generated by human motion.The applications of recycling these scattered mechanical energy to provide energy for sensors or as trigger signals for sensors have a bright future.Triboelectric Nanogenerator(TENG)enables the triboelectrification effect in the environment to be studied and widely applied.TENG can be used to collect various forms of mechanical energy,such as wind energy,sound wave,water flow,raindrop,wave energy in nature.In addition,human activities also produce a lot of mechanical energy,such as heartbeat and respiration.The wearable device based on TENG can convert the mechanical energy generated by these physiological activities into electrical signals to realize self-powered sensing.The existing TENGs have been widely used in various sensing fields.Customized selfpowered sensors adapted to specific application scenarios often cannot meet the use requirements of other application scenarios.Therefore,it is difficult for TENG to be reused,which leads to a waste of resources and a negative impact on the environment to a certain extent.However,researchers pay less attention to the TENG sensors with variable stiffness and reconfigurable characteristics.Nature can inspire scientific research and technological innovation.Organisms have experienced long-term natural selection,and their body structure and behavior characteristics have evolved into the optimal combination in the living environment.Studying biological structure and behavior has become an effective strategy to solve engineering problems.For different needs,bionic ideas can provide inspiration.Although the existing TENG designs have begun to learn from biology,there are few relevant applications,and biology still has many excellent characteristics that deserve further learning and imitation.From the perspective of bionics,this paper studies the above problems.The main research contents are as follows:(1)Based on the principle of bionics,a biomimetic multistage structure film processing method was developed by learning from typical organisms such as small intestinal villi and lotus leaf surface.The film prepared by this method has multistage surface microstructure with controllable size,good integration,and good hydrophobic characteristics.When the tensile strain reaches 300%,the superhydrophobic state can still be maintained,which provides a strong guarantee for the application of biomimetic films in humid environment.At the same time,the multistage structure can increase the surface area of the biomimetic film,thereby effectively improving the power generation efficiency when it is used as the friction layer of TENG so that it has the potential to be applied in power generation devices and sensor basic elements.(2)In order to solve the problem of large-area preparation of biomimetic thin films,a method for rapid preparation of biomimetic thin films was developed.This method has the advantages of simple operation,low cost,and suitable for large-scale preparation.At the same time,the method makes a better combination between the substrate and the superhydrophobic particles by using the dissolution characteristic between substances.In addition,due to the good electron affinity of the substrate,the biomimetic film prepared can be used as a friction layer for TENG that requires hydrophobic properties.At the same time,the corona charging method is used to improve TENG output performance.This method can significantly increase the surface charge density of the friction layer and thus improve the output power of TENG.(3)Based on the research of biomimetic thin films,different solutions are proposed to solve the problems of low power generation efficiency of contact-separation mode TENG and easy wear of freestanding triboelectric-layer mode TENG.One is the contact-separation mode TENG used for swing low-frequency mechanical energy collection,which can increase the output power by increasing the synchronous working units without increasing the operating frequency of the driver.The multiple synchronous working units are small in size and can be arranged freely,which is conducive to the overall compact layout.In addition,the operation rules of multiple TENGs are consistent,which is conducive to the integrated output of electric energy while improving the power generation efficiency.The other is freestanding triboelectric-layer mode TENG which can switch working state freely.At the initial stage of the work,it is in the contact electrification stage,which can saturate the charge density on the surface of the friction layer,and then enter the non-contact freestanding triboelectriclayer working mode.There is no friction between the friction layers at this stage,so the driving resistance can be reduced and the service life of the TENG can be improved.(4)Aiming at the problem that the existing TENGs have a small application range and cannot be reused in other application scenarios,a simple and efficient fiber reconfigurable manufacturing technology is developed based on low melting point alloys,electric heating wires,and conductive wires.The reconfigurable fiber TENG prepared by this technology can obtain energy in the environment through triboelectrification.The stiffness of the fiber TENG can be changed by heating or cooling the low melting point alloy.Therefore,they can easily deform in a low stiffness state to form a new structure and maintain the deformed structure at normal temperature to adapt to new applications,including a variety of 2D and 3D fiber TENGs.This breaks through the application limitations of the existing TENGs and will reduce the time for preparing TENG again and reduce the waste of resources.The reconfigurable feature can enable TENG to be reused in different application scenarios,such as wearable rehabilitation equipment,self-powered tactile sensing system,and mechanical flaw detection application. |
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