Terahertz Absorbing Material With Three-Dimensional Composite Structure Based On MXene

In recent years,terahertz technology has developed rapidly and has been widely concerned by countries all over the world.Due to its low energy,good coherence,high imaging resolution and many other characteristics,terahertz waves have shown very important application prospects in radar stealth,security imaging,and wireless co mmunications.Moreover,with the rapid development of electromagnetic shielding technology,the demand for high-efficiency and broa d Band terahertz absorbing materials is also increasing.At present,terahertz absorbing materials mainly follow the four main points of thin thickness,light weight,large absorption bandwidth,and high absorption strength.However,most of the current terahertz absorbing materials have the disadvantages of expensive preparation cost,high surface reflectivity,narrow absorption bandwidth,weak absorption strength,poor mechanical properties,and poor material stability,making it difficult to effectively put into practical application.Based on the above background,this paper has carried out research on MXene-based terahertz absorbing materials with large bandwidth,high absorption strength,low cost and superhydrophobic function.The specific research results are as follows:First of all,this paper studies the terahertz film absorbing materials based on two-dimensional MXene nanomaterials.Taking advantage of the high conductivity and high specific surface area of the two-dimensional MXene nanomaterials,the MXene film with a thickness of several micrometers was prepared by the method of vacuum filteration.Taking advantage of the high conductivity and high specific surface area of the two-dimensional MXene nanomaterials,the MXene film with a thickness of several micrometers was prepared by the method of suction filtration.At the same time,it is proved that MXene film has a certain absorptivity(average absorptivity is about 50%)and almost no transmittance for terahertz wave by using terahertz test system,which effectively proves that MXene film is a kind of terahertz absorbing material with weak absorptivity.Then,in order to further improve the absorption efficiency of the absorbing material,we prepared the MXene sponge foam(MSF)absorbing material by mixing polyurethane foam with MXene solution by direct i mmersion.This kind of absorbing material has many advantages,such as low mass density,strong flexibility,high absorption efficiency,low preparation cost,simple manufacturing process and so on.It highlights its excellent practical application value.At the same time,by comparing the three variables of different MXene nanosheet loading,different aperture and different thickness,it was finally confirmed that the MXene absorbing foam with a thickness of 2mm and pore per inch(ppi)of 50 ppi has the best absorption effect on terahertz waves in the frequency range of 0.3THz to 1.65 THz,and achieved a high absorption rate of99.99% and a low reflectivity of 0.00003%.It effectively proves that the MSF we prepared is a broa d Band terahertz absorbing material with strong absorption effect.Finally,in order to further improve the validity and stability of absorbing materials in harsh environments such as rainy and ice,we use different kinds of silane coupling agents and silica particles to hydrophobically modify the MSF sample,and finally get a terahertz absorbing material with both superhydrophobic properties(hydrophobic angle greater than 150°,rolling angle less than 10°)and high absorption efficiency(greater than 99%).