Construction And Performances Of Janus Film Simultaneously Endowed With Double Anisotropic Conductive-Magnetic-Luminescent Multifunctionality

At present,there are mainly two types of anisotropic conductive films（ACFs）.Among them,the type I anisotropic conductive film is conductive along the film thickness direction and the insulative along the membrane surface,and has been widely used in the fields of electronic industry and sensors;the type II anisotropic conductive film has different conductivity along the two vertical directions of the membrane surface and insulation along the film thickness direction,and is still in the laboratory exploration stage.The research and development of new-typed multifunctional anisotropic conductive films has become one of the hot research topics in the field of electronic industry and material science.One-dimensional（1D）nanomaterials with luminescent-conductive-magnetic（denoted as LCM）multi-functionalities have become one of the frontier research hotspots of multifunctional materials.Compared with single functional materials,LCM multifunctional materials have broader application prospects.However,when the luminescent,conductive and magnetic materials are directly mixed mutually,unfavorable interferences will occur.In order to reduce the adverse effects of various materials to improve the properties of materials and meet the requirements of special electronic devices for conductive direction,it is necessary to construct LCM multifunctional 1D nanomaterials with special structures.In this dissertation,detailed study on two research hotspots of LCM multifunctional 1D nanomaterials and ACFs as well as their combinations are performed.Janus film with synchronous polyfunctions of double anisotropic conduction,magnetism and luminescence is devised and synthesized via electrostatic spinning technique by using 1D nanostructure as the building units.Then,two-dimensional（2D）Janus film is rolled up with different strategies to obtain novel three-dimensional（3D）dual-wall Janus tubes and 3D+2D complete flag-shaped structures.Furthermore,fluorene photoconductive materials are innovatively introduced into Janus films to obtain anisotropic photoconductive films.By using light to control the insulation and conductive state of anisotropic photoconductive film（APF）,the conversion between non-anisotropic and anisotropic conductivity is realized.In addition,in order to further improve the LCM properties of the material,a new-typed pseudo-Janus structure,very different from the Janus structure,is proposed.The pseudo-Janus structure has different symmetries from the traditional Janus structure.Functional partition is macroscopically increased,and further,the micro-partition and macro-partition are highly integrated to achieve excellent multi-function.The main research contents are as follows:1.{[Eu（BA）3phen/polymethyl methacrylate（PMMA）]//[polyaniline（PANI）/PMMA]}⊥{[Eu（BA）3phen/PMMA]//[PANI/PMMA]}&[Fe3O4/polyvinylpyrrolidone（PVP）]red luminescent-magnetic-double anisotropic conductive bi-layer Janus film and{[PANI/PMMA]//[PMMA/Tb（BA）3phen]⊥[PANI/PMMA]//[PMMA/Tb（BA）3phen]}&[Fe3O4/polyacrylonitrile（PAN）]bi-layer Janus film with green luminescence-magnetism-double anisotropic conduction are prepared by using bi-axial parallel electrospinning and uniaxial electrospinning.The critical thickness,magnetism,luminescence and conductivity of the Janus film have been studied in detail,and the mechanism of the interactions among LCM performances is clarified.By using Janus nanobelts as building units,the adverse effects among luminescence,conductivity and magnetism are reduced,and thus,the top layer achieves excellent luminescence properties and high anisotropic conductivity.By changing the contents of rare earth complexes,Fe3O4 nanoparticles and PANI,the tunable luminescence,magnetism and anisotropic conductivity of bi-layer Janus film is obtained.Micro-partition and macro-partition are highly integrated in the array film to achieve excellent multi-functions.2.For the first time,new concepts of 3D dual-wall Janus tube and 3D+2D complete flag-shaped structure are proposed.Firstly,{[Eu（BA）3phen/PMMA]//[PANI/PMMA]}⊥{[Tb（BA）3phen/PMMA]//[PANI/PMMA]}&（Fe3O4/PMMA）Janus film with double anisotropic conductivity,magnetism and green-red luminescence,{[Fe3O4/PMMA]//[PANI/PMMA]}⊥{[Eu（BA）3phen/PMMA]//[PANI/PMMA]}&[Tb（BA）3phen/PMMA]magnetic,red luminescent-double anisotropic conductive and green luminescent Janus film and{[Fe3O4/PMMA]//[PANI/PMMA]}⊥{[Tb（BA）3phen/PMMA]//[PANI/PMMA]}&[PMMA/Eu（BA）3phen]Janus film with red luminescence,conductivity,magnetism and green luminescent-double anisotropic are designed and constructed by electro-spinning technology.Then the three kinds of Janus films are rolled up in different ways to obtain 3D dual-wall Janus tube and 3D+2D complete flag-shaped structure.The inner tube or outer tube of the dual-wall Janus tube is Janus structure,and the complete flag-shaped structure reflects the successful combination of 2D Janus film and 3D dual-wall Janus tube.The above 3D structures have similar performance to the 2D Janus film.In addition,the structure and properties of 3D or 3D+2D materials can be adjusted by changing the properties of different functional regions and the arrangement of Janus nanobelts.The new findings provide a new idea for the design and construction of new multifunctional nanomaterials.3.Anisotropic electric conduction is realized by using photoconductivity phenomenon,and the new concepts of anisotropic photoconductive film（defined as APF）,light stimulation response enhanced anisotropic photoconductive Janus film（denoted as L-ACJM）and switch-type anisotropic photoconductive Janus film（named as SAPJF）are proposed.[High concentration 2,7-dibromo-9-fluorenone（H-DF）/polyvinylidene fluoride（PVDF）/PVP]//[lowconcentrationDF（L-DF）/PVDF/PVP]APF,[PANI/DF/PMMA]//[Eu（TTA）3（TPPO）2/PMMA]&(Na YF4:Yb³⁺,Tm³⁺/PAN)L-ACJM and[high concentration DF（H-DF）/PVDF/PVP]//[Fe3O4/PVDF/PVP]&[low concentration DF（L-DF）/PMMA]SAPJF are designed and constructed by using electrospinning technology.Under ultraviolet light illumination,the Janus nanofibers/nanobelts are conductive along the length direction of Janus nanofibers/nanobelts and insulative in the direction perpendicular to the length of Janus nanofibers/nanobelts,leading to conductive anisotropism.When ACFs contain PANI,the conductivity and anisotropic degree of ACFs can be improved by the transition from without light illumination to light illumination.The effects of DF content and different template polymer on the photoconductivity of the products are studied,and the influencing mechanism is revealed.The transition from monomer emission（purple luminescence）to excimer emission（green luminescence）of DF is realized by modulating the different concentration and existing environment of DF.Through using different rolling strategies to roll up the 2D anisotropic photoconductive film,novel 3D and 3D+2D materials with good anisotropic photoconductivity,magnetic and luminescence properties are obtained.4.Inspired by Yin-Yang Fish sign in the Tai-Chi Symbol,a brand-new concept of structure different from Janus structure is proposed,and it is defined as pseudo-Janus structure.The pseudo-Janus structure can be regarded as a new structure which is obtained by flipping one side of the Janus structure vertically.The Yin-Yang Fish sign is a typical pseudo-Janus structure.Herein,employing Yin-Yang Fish structure film representing pseudo-Janus structure as a case study,we have fabricated a pseudo-Janus structure film（defined as PF）with multi-modes luminescence and double-anisotropic conductivity by electrospinning.The two fish-like structure regions of PF are respectively constructed by[(Na YF4:Yb³⁺,Er³⁺)/PMMA]//[PANI/PMMA]Janusnanobeltsand[(Na YF4:Eu³⁺)/PMMA]//[PANI/PMMA]Janus nanobelts,and the two eye-like regions respectively consist of Tb（BA）3phen/PVP nanofibers and Eu（BA）3phen/PVP nanofibers.Macroscopically,PF achieves four independent functional domains.Microscopically,the Janus nanobelt achieves two functional domains.Micro-partition and macro-partition are highly integrated in the PF to achieve excellent multi-functionality.Therefore,PF has excellent synchronous double-anisotropic conduction,up-and down-conversion multi-modes luminescence.Pseudo-Janus structural design is also applicable to construct other multi-functional materials with different structures or properties.