Assembly And Performances Of Anisotropic Electrically Conductive Janus Film Functionalized By Magnetism And Luminescence

With the continuous development of nanotechnology,higher requirements for nanomaterials have been put forward.Fluorescent-conductive-magnetic multifunctional nanomaterials(names as FCMMNs)have become one of the frontier research hotspots in the field of materials science due to their unique multi-functionalities.Such novel nanomaterials have important applications in the fields of electromagnetic shielding and flexible nanodevices.In order to ensure that the various functions of the luminescent-conductive-magnetic multi-functional nanomaterials are independent and highly integrated,it is necessary to avoid the adverse mutual effects among the functions and carry out reasonable structural design in the process of designing the multi-functional,so as to effectively avoid the harmful interaction among different functions and obtain excellent multi-functional properties.Research and development of FCMMNs with novel structures and excellent performances will play an important role in promoting the development of multifunctional nanomaterials,nanodevices and other fields.In this dissertation,the design strategy of combining micro-partition with macro-partition is proposed,and one-dimensional nanobelt,nanofiber,Janus nanobelt and Janus nanofiber are designed and prepared by electrospinning.By using these one-dimensional nanostructures as micro building units,new-type Janus films with special macro structures and a variety of derived three-dimensional Janus tubes are assembled.The harmful interferences among different functions are obviously reduced microscopically and the integration of anisotropic conductivity,fluorescence and magnetism is macroscopically realized by the aid of the structural advantages of Janus materials.Furthermore,conductive-fluorescent bifunctional Janus nanobelts array and fluorescent Janus nanofibers membrane doped with carbon nanotubes(CNTs)are prepared by respectively applying Janus nanobelt and Janus nanofiber as building units,and then two kinds of triboelectric nanogenerators(TENG)are manufactured via using the prepared materials.The morphologies,structures and properties of the materials as well as the electrical output performance of TENG are studied in detail.The details are as follows:1.By using the design strategy of combing micro-partition with macro-partition,Janus-like nanoribbons are prepared by parallel electrospinning technology,and then used as microscopic construction units to fabricate conductive-fluorescent layer and magnetic-fluorescent layer,and the two layers are successfully assembled into anisotropic conductive-magnetic-fluorescent Janus-like film(named as CML Janus-like film)with top-bottom structure.Special Janus-like nanoribbon realizes the micro-partition by limiting different functional materials in their own domains,effectively reducing the harmful interferences between different functions and ensuring the high conductivity anisotropy of CML Janus-like film.Janus-like film structure can realize macro-partition and further reduce the harmful effects among various functions,and achieve the high integration of high conductivity anisotropy,adjustable magnetism,red and green fluorescence in CML Janus-like film.Such design concept that combines micro-partition with macro-partition can be extended to assemble other multifunctional materials.2.Inspired by Bicker square(Rubik's Cube),modular structure and design philosophy of multifunctional materials is put forward.Different micro building units are fabricated via electrospinning and used to assemble different functional modules,and then four module structure electrically conductive anisotropic-magnetic-fluorescent Janus film(marked as 4M-EMF Janus film)and multiple anisotropic conductive-magnetic-fluorescent Janus film(called as MCML Janus film)are successfully by using different functional modules.The modular structure and Janus structure realize the integration of different functional modules and macro functional partitions.Moreover,the micro-partition of different functions is realized and the mutual harmful influences among three functions are effectively reduced through the reasonable micro design in each functional module to obtain high anisotropic conductivity,adjustable magnetism and fluorescence.Modular design philosophy provides a flexible design concept and preparation method.A variety of multifunctional materials can be gained to meet different requirements by regulating the compositions,quantities,arrangements and directions of different modules.3.Based on the characteristics and advantages of modular structure and Janus structure,nanofiber and Janus nanobelt are fabricated by electrospinning and acted as building units to prepare different functional blocks which are successfully assembled into three block structure anisotropic conductive-magnetic-fluorescent Janus-type film(named as 3B-CML Janus-type film)and semi-bianisotropic conductive-magnetic-fluorescent Janus-structure film(defined as SCMF Janus film).Different micro construction units,macro module structure and Janus structure realize the high integration and mutual independence of the different functions in the materials.Meanwhile,three-dimensional Janus tubular materials are successfully constructed through different preparation strategies to roll up the flexible two-dimensional 3B-CML Janus-type film and SCMF Janus film,thus realizing the high integration of zero-dimensional nanoparticles,one-dimensional micro building units,two-dimensional Janus membrane and three-dimensional Janus tube in one material.Such multifunctional nanomaterials have potential application prospects in the fields of flexible nanodevice,triboelectric nanogenerator,electromagnetic shielding,etc.4.Based on the structural characteristics and advantages of Janus materials,conductive-fluorescent Janus nanobelt array(defined as JNA)and PVDF/PVP composite nanofiber membrane are respectively constructed by using parallel electrospinning technology and single axial electrospinning technology,and then a fluorescent triboelectric nanogenerator(marked as TENG-JNA)is firstly manufactured by applying JNA and PVDF/PVP composite nanofiber membrane.JNA can concurrently act as the charge-generating layer and the charge-trapping layer,when the Cu electrode attached to JNA is used as the charge-collecting layer,and the load acts as the charge-storage layer of TENG-JNA.The micro building unit of JNA is[PANI/CNTs/PMMA]//[Tb(BA)₃phen/PMMA]Janus nanobelt which can realize the integration of charge-generating layer and the charge-trapping layer in JNA,and achieve the micro separation of conductive and fluorescent materials by using the asymmetric structure,so TENG-JNA concurrently has good electrical output performance and green fluorescence.The maximum output current of TENG-JNA is 6.2?A and the maximum output voltage is155 V,and TENG-JNA has excellent output stability.The successful construction of TENG-JNA promotes the applications of conductive-fluorescent Janus nanomaterials in the field of TENG,and then further provides theoretical,material and technical supports for the development of new-typed building units of TENG.Such design concept and construction technology can be extended to assemble other novel TENG.5.In order to give full play to the advantages of Janus materials in the construction of TENG,[CNTs/PVDF/PVP]//[Eu(TTA)₃(TPPO)₂/PVDF/PVP]Janus nanofiber membrane(defined as JNM)and PMMA nanobelt array are constructed by respectively using parallel electrospinning technology and single axial electrospinning technology,and then used to assemble triboelectric nanogenerator(called as TENG-JNM).JNM can concurrently act as the charge-generating layer and the charge-trapping layer,when the Cu electrode attached to JNM acts as the charge-collecting layer and the load is equivalent to the charge-storage layer of TENF-JNM.Carbon nanotubes(CNTs)are introduced into JNM to increase the content of?phase in PVDF and improve the flexibility of JNM.Janus nanofiber with the asymmetric structure is used to realize the micro separation of fluorescent substances from dark CNTs,and achieves the integration of charge-generating layer and charge-trapping layer in JNM.As a result,TENG-JNM simultaneously has strong red fluorescence and high electrical output performance.The maximum output current of TENG-JNM is 22.4?A and the maximum output voltage is 353 V.Janus nanofiber with special partition structure can ensure that TENG-JNM has improved output performance and other excellent properties,such as hydrophobicity,flexibility,light weight,etc.TENG-JNM has important applicative prospects in the fields of flexible devices and electronic skin.