Structure Design Of Fe₃O₄/Ti₃C₂T_x Composites With Tunable Electromagnetic Wave Absorption Performance

With the development of electronic information technology,electronic communication devices such as mobile phones are widely used.Although they bring convenience to people’s lives,electromagnetic pollution cannot be ignored.To solve this problem,researchers have been working on the development of high performance electromagnetic wave absorption materials.A good absorbing material must meet the requirements of a small thickness of absorbing layer,light weight of absorbing agent,a wide range of absorbing frequency,and high absorbing strength.Traditional absorbers(such as metallic materials,carbon materials,etc.)are not able to meet the requirements of modern absorbers due to their single component,unsatisfactory impedance matching,and high density.High performance wave absorbing materials should have suitable impedance matching and good attenuation of electromagnetic waves.Electronmagnetic wave adsorption composites could provide a variety of loss mechanisms while optimizing impedance matching due to their component diversity and structural designability,which can effectively improve absorbing performance.Therefore,composite absorbing materials with specific structures stand out among the many absorbing materials and have great research value.Magnetite(Fe3O4)is widely used in wave absorbing composites to provide magnetic loss due to its inherent magnetic properties.As one of the new two-dimensional materials,Ti3C2Tx has great potential for applications in wave absorption due to its high electrical conductivity,good mechanical properties,and structural design ability.This study design and synthesize Fe3O4/Ti3C2Tx composites with with different structures including layered semi-covered,corallite and porous aerogel.The reflection loss of the Fe3O4/Ti3C2Tx composites is measured to evaluate electromagnetic wave adsorption.The parameters that affect the electromagnetic wave adsorption perofermance are summarized.(1)Ti3C2Tx in flake form was prepared from Ti3AlC2 using an in-situ etching method.Hollow Fe3O4 particles of uniform particle size were prepared using the solvothermal method,and the HFO was treated by PDDA.Finally,Fe3O4/Ti3C2Tx composites with a layered semi-covered structure were prepared by using electrostatic self-assembly.The electromagnetic parameters can be modified by changing the mass ratio of Fe3O4 and Ti3C2Tx in the composite.When the mass ratio of Fe3O4 to Ti3C2Tx is 1:2,the RLmin and optimum EAB could be-35.8 dB and 4.4 GHz with thickness of 2.0 mm.When the mass ratio of Fe3O4 to Ti3C2Tx is 2:1,the RLmin is improved to-57.17 dB at 6.65 GHz with thickness of 1.8 mm.The impedance matching and interfacial polarization of the material can be effectively enhanced by modulating the components and structure.(2)Ti3AlC2 was used as the raw material for the preparation of Ti3C2Tx flakes by in-situ etching.PMMA microspheres were then prepared by emulsion polymerization.The Ti3C2Tx/PMMA microspheres were produced by electrostatic self-assembly.Hollow Fe3O4 particles were produced by the hydrothermal method.Then the Hollow Fe3O4 particles were treated by CTAB.Fe3O4/Ti3C2Tx/PMMA microspheres were prepared by electrostatic self-assembly method.Finally,Fe3O4/Ti3C2Tx composites with corallite structure were prepared by annealing treatment.When the mass ratio of Fe3O4 to Ti3C2Tx is 1:1,the RLmin and optimum EAB could be-42.48 dB and 1.99 GHz with thickness of 3.1 mm.When the mass ratio of Fe3O4 to Ti3C2Tx is 2:1,the RLmin and optimum EAB could be-16.54 dB and 3.63 GHz with thickness of 2.5 mm.And as the HFO content increases,the change in the absorbing strength of the composites corresponds to the change in structure,proving that the correlated structure has an effect on the absorbing properties.(3)Accordion shaped Ti3C2Tx and lamellar Ti3C2Tx were prepared from Ti3AlC2 using HF etching and in-situ etching,respectively.Fe3O4@Ti3C2Tx was then prepared by compounding organ-shaped Ti3C2Tx with Fe3O4 using the solvothermal method.PAA was mixed with flakes of Ti3C2Tx and Fe3O4@Ti3C2Tx and lyophilized to obtain a mixed aerogel.The Fe3O4@Ti3C2Tx/Ti3C2Tx/polyimide composite aerogel was prepared after annealing treatment.When the mass ratio of Fe3O4@Ti3C2Tx to Ti3C2Tx is 1:1,the RLmin and optimum EAB could be-52.96 dB and 4.64 GHz with thickness of 2.89 mm.This demonstrates that combining macro and micro structures can effectively improve the electromagnetic wave absorption properties of composite materials.