Preparation And Properties Of MXene/ANF Composite Films By Vacuum Assisted Filtration

Traditional electromagnetic shielding materials usually use conductive metal,conductive rubber,conductive compound,etc.,but the obvious drawbacks are that these materials are easy to corrode,heavy,and not easy to bend.Therefore,in order to overcome various defects brought by the limitations of traditional shielding materials,the development of electromagnetic shielding multifunctional materials with flexibility and excellent mechanical properties is of great significance for the next generation of smart electronic devices and communication applications.In this dissertation,two 2D highly conductive MXene materials with layered structure and 1D nanofiber aramid nanofibers（ANF）with strong mechanical properties and thermal stability were selected to prepare two kinds of alternately laminated structure composite multifunctional films.The main work was as follows:（1）Preparation and properties of alternately laminated ANF/MXene composite films.Aramid nanofibers/Ti₃C₂T_x MXene（ANF/MXene）composite films with multilayer structure were successfully prepared by a simple alternating vacuum-assisted filtration（AVAF）process.With the intervention of the ANF layer with strong mechanical properties and thermal stability,the laminated structure film exhibits excellent mechanical properties.The tensile strength of the ANF2/MXene1 composite film can reach 177.7 MPa,and the fracture strain was 12.6%.In addition,the electromagnetic interference（EMI）shielding efficiency of the ANF5/MXene4composite film with a thickness of only 30μm was 37.5 d B,while the high EMI shielding effectiveness value of the thickness（SSE/t）was 4718 d B cm~2 g^-1.In addition,the composite film has excellent thermal insulation properties and avoids light-to-heat conversion.At a high temperature of 130°C,the surface of the film with a thickness of only 100μm did not produce a burning sensation.Additionally,the film surface was only gentle to the touch under simulated sunlight.Therefore,our multilayer structured films have potential implications in practical applications such as smart electronic devices,communications,and military applications.（2）Preparation and properties of alternately laminated ANF/MXene@AgNW composite films.Alternately stacked ANF/MXene@AgNW thin films were fabricated by AVAF process with the addition of silver nanowires.The three-dimensional conductive structure formed by silver nanowires and MXene nanosheets,and presence of ANF substrate,the composite film has excellent mechanical properties and ultra-high electromagnetic shielding properties.Among them,the ultra-thin thickness alternately laminated composite ANF2/MXene@AgNW1 film has a tensile strength exceeding 200 MPa.In particular,the electromagnetic shielding properties of the ANF/MXene@AgNW composite films are far superior to those of the ANF/MXene films,and the overall average shielding efficiency can reach more than 99.99%.In addition,the ANF/MXene@AgNW composite film has excellent performance in electrothermal conversion.The film can be heated up to 111.5°C by applying low pressure,and the temperature can be controlled within the range of 50-100°C by adjusting the voltage.Application and many occasions.In summary,this kind of alternate laminated composite shielding film with simple manufacturing process and wide application has potential significance in practical applications such as aerospace、removable devices、and smart terminal.