Study On Structure Design And Electromagnetic Interference Shielding Performance Of Lightweight Porous Conductive Fabric/Aerogel

With the rapid development of information technology,environmental pollution caused by high-power electromagnetic radiation has caused widespread concern.The existing shield material(metal plate)has shortcomings such as high specific gravity and poor flexibility,and it is difficult to meet the requirements of complex applications such as light weight and wearable.The electromagnetic parameters of ordinary textile materials cannot reach the order of magnitude that metals and semiconductors have,and they do not have any electromagnetic functions.How to design lightweight and porous electromagnetic interference shielding materials to meet the application fields related to wearable electronics has become a hot research topic.This paper uses wet chemical method,magnetron sputtering and freeze-drying techniques to obtain conductive fabrics and aerogels with lightweight and porous characteristics,and explores the relationship between their structure and electromagnetic interference shielding performance.The specific research content is as follows:Two kinds of PET non-woven fabrics with non-woven and knitted structures are selected as base fabrics,and two conductive fabrics with excellent electromagnetic shielding performance are prepared by in-situ polymerization of PPy and subsequent electroless nickel plating.Through the analysis of simplified fabric structure and fractal dimension,the relationship between fabric structure and electromagnetic shielding effectiveness is discussed.Among them,the conductivity and electromagnetic shielding performance of Ni/PPy/NW-PET conductive fabric can reach 96.32?^-1 cm^-1 and 77.87dB,respectively,which is higher than that of Ni/PPy/WK-PET conductive fabric(91.71?^-1 cm^-1,62.6dB)is even better.Research on the correlation between fractal dimension and electromagnetic shielding effectiveness shows that NW-PET has a higher fractal dimension than WK-PET,and the fractal dimension of conductive fabrics obtained under the same preparation process is also higher.In addition,the Ni/PPy/NW-PET conductive fabric with excellent electromagnetic shielding performance shows excellent bendability,heat-moisture stability and washing stability.Furthermore,the fabric also shows the potential to be applied to wearable fabric antennas.Through the structural design of the microstrip fabric antenna,the reflection coefficient and antenna gain can reach approximately-32.08dB and 2.76dB,respectively.This study reveals the relationship between fiber structure,porosity and fractal dimension,conductivity and electromagnetic shielding effectiveness,and may provide a novel research idea for the development of high-performance conductive fabrics.For functional fabrics,the simple electromagnetic shielding function seems to have been unable to meet people's daily needs.Infrared light is also a kind of electromagnetic wave.The development of infrared reflective coating plays a vital role in protecting objects from infrared radiation.The conductive particles formed on the surface of the fabric by the above-mentioned wet chemical method are distributed disorderly,while the magnetron sputtering technology uses the action of electric and magnetic fields to sputter the target particles onto the fabric substrate and ensure that the target particles can be It grows conformally with the fabric fibers,maintaining the flexibility of the fabric itself.In this study,DC magnetron sputtering was used to prepare Cu/NFs/PET composite fabric.When the sputtering time was 15 min,the total shielding performance reached 55.84dB,and when the sputtering time was 20 min,the SE_T could reach 61.32dB.Both exhibit good electromagnetic interference shielding performance.At the same time,a Cu/NFs/PET composite fabric with a sputtering time of 15 min was selected as the substrate,and a Ti O2 film was sputtered on it by radio frequency magnetron sputtering.The color of the obtained fabric is controllable,and the color of the fabric can be changed from yellow to yellow with the titanium dioxide sputtering time.Rich color variations of purple.Thanks to the design of the titanium dioxide/copper composite structure,this flexible and breathable multifunctional fabric has excellent electromagnetic shielding performance(55.84dB)and infrared stealth performance,paving the way for the development and research of wearable devices.In addition to preparing functional fabrics with good electrical conductivity and excellent electromagnetic shielding properties based on fabrics,this research also designed a conductive polymer aerogel with a three-dimensional conductive network structure.The extremely high conductivity will cause most of the electromagnetic waves to be reflected when incident on the surface of the shielding body,causing secondary pollution.Conductive aerogels with high porosity can absorb electromagnetic waves incident on the body through multiple reflections.The carbon nanotube/polypyrrole hydrogel is prepared through heterogeneous reaction,and then freeze-dried to prepare the carbon nanotube/polypyrrole aerogel.When the content of carbon nanotubes is 0.56%,the electromagnetic absorption performance of carbon nanotube/polypyrrole aerogel is the best.It reflects reflection when maintaining an apparent density of 56.64 mg cm^-3 and a porosity of 95.25%.The loss reached-49.63dB.As a wave absorber with excellent electromagnetic wave absorption performance,it can be widely used in the field of electromagnetic interference shielding.