Fabrication Of ZnO Nanorods@carbon Fiber Composites And Study On Electricity Generation Performace

With the progress towards intelligent lifestyle,materials with single property can not meet the requirements to prepare new functional devices.Carbon fiber is a new material with excellent mechanical properties and good electrical conductivity.By introducing piezoelectric ZnO nanorods onto the surface of carbon fibers,a composite which can convert mechanical energy into electrical energy can be prepared.However,the weak bonding strength and low barrier height between carbon fibers and ZnO nanorods are the key factors that restrict the efficiency and reliability of the composite system.In this thesis,dense and uniform ZnO nanorods arrays were synthesized on the surface of carbon fibers by hydrothermal method.Furthermore,the bonding strength and barrier height between the ZnO nanorods and carbon fibers were controlled by magnetron sputtering.Finally,the composite with excellent mechanical strength and self generating performance was prepared.Firstly,ZnO nanoparticles were prepared by solvothermal method,which were uniformly adhered on the surface of carbon fibers.Then,dense and uniform ZnO nanorods were synthesized on the surface of carbon fibers using ZnO nanoparticles as seed by simple hydrothermal method.ZnO nanorods with different lengths could be synthesized by controlling the growth time.The resin wettability test of carbon fibre showed that the wettability was improved significantly after the modification by ZnO nanorods.Meanwhile,the interfacial shear strength of carbon fiber reinforced resin composites was significantly improved after the modification by ZnO nanorods owing to the mechanical locking effect between ZnO nanorods and resin matrix.SEM measurement indicated that the interface between ZnO nanorods and carbon fibers was the weak point of the composites,where the fracture occured firstly.Therefore,improving the bonding strength between ZnO nanorods and carbon fibers could further enhance the mechanical properties of the composites.The uniform ZnO films were prepared on the surface of carbon fibers by magnetron sputtering.Dense and uniform ZnO nanorods arrays were fabricated by using the ZnO films as seeds.By changing the parameters of magnetron sputtering,the interfacial bonding strength between ZnO nanorods and carbon fibers was effectively improved.XPS measurement indicated that the chemical bond formed between ZnO and carbon fibers during magnetron sputtering.High resolution TEM observed the crystal structure relationship among carbon fibers,ZnO films and ZnO nanorods.The results showed that there were coherent relationships among them.The epitaxy growth mechanism between ZnO films and carbon fibers was demonstrated,which ensured the effective bonding strength between them.The electrical properties of the interface between ZnO nanorods and carbon fibers were also tested.The results showed that the Schottky barrier height of the interface between ZnO nanorods and carbon fibers could be adjusted by changing the parameters of magnetron sputtering.The optimization of mechanical and electrical properties between ZnO nanorods and carbon fibers created conditions for the preparation of multi-functional composites based on ZnO nanorods@carbon fibers.Firstly,the polymer protective layer on the surface of carbon fibers was used as the charge storage barrier between the carbon fibers and the ZnO nanorods.Based on the simple design,the hybrid nano-generator which could convert the mechanical energy into electrical energy was prepared,and the output electric was 2 m V,0.2 n A.Then the bonding strength and barrier height between ZnO nanorods and carbon fibers were further adjusted by magnetron sputtering.A layer of silicone resin was filled in the gap between the ZnO nanorods to further protect the ZnO nanorods.Finally,a layer of metal film was used as another electrode,and the ZnO nanorod@carbon fiber composite with excellent mechanical properties and power generation performance was prepared.Based on a single carbon fiber,60 m V,0.6 n A electric energy was produced under stress and deformation.Moreover,40 m V,6 n A electric energy was outputted by the nano-generator based on a bunch of carbon fibers.Compared with the former nano-generator,both the stability and power generation performance were significantly improved.By calculation,the current density of the nano-generator reached 0.227 ?A/cm~2 based on a single carbon fiber.Therefore,the composites demonstrated broad application in self-generation and intelligent equipment.