The development of high-frequency and high-speed 5G communication technology and high-integration, thin and light intelligent electronic products has facilitated people's production and life, while highlighting the seriousness of electromagnetic interference. Electromagnetic interference can cause negative effects such as signal interception and data loss, and seriously affect the performance and normal operation of electrical and electronic equipment. The development of new electromagnetic shielding materials is a key technology to solve electromagnetic pollution, especially high-performance electromagnetic shielding materials that are ultra-thin, lightweight, and have excellent mechanical strength and reliability. Carbon nanotubes have extremely high electrical conductivity and mechanical properties, and have a wide range of potential applications in the field of electromagnetic shielding. However, when carbon nanotubes are assembled into a macroscopic shield (such as carbon nanotube film), their electrical conductivity and mechanical strength are less than one-tenth of that of a single carbon nanotube. This is mainly due to the It is caused by weak interaction force between tubes and high contact resistance. How to effectively enhance the interaction between carbon nanotubes and improve the mechanical, electrical conductivity and shielding properties of carbon nanotube films is of great significance.
Recently, Sun Rong’s team, a researcher from the Institute of Materials Science and Technology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, published an update on ACS Nano with the topic Ultrathin Densified Carbon Nanotube Film with “Metal-like” Conductivity, Superior Mechanical Strength, and Ultrahigh Electromagnetic Interference Shielding Effectiveness Research results. This research work provides a new method for the development of ultra-thin, lightweight and high-performance shielding films.
The researchers first used high-temperature annealing and acid treatment processes to remove impurities in the carbon nanotube film, and then treated with chlorosulfonic acid to separate positive and negative charges on the surface of the carbon nanotubes, thereby enhancing the interaction between the tube and the tube. A carbon nanotube film with a dense structure was developed. The dense carbon nanotube film exhibits ultra-high shielding effectiveness and excellent mechanical strength. The thickness of the carbon nanotube film is only 1.85 microns, and the shielding effectiveness is as high as 51 dB. When the thickness is increased to 14.7 microns, the shielding effectiveness is further improved to 101 dB. In addition, due to the extremely strong interaction force between the tube and the tube, the tensile strength of the densified carbon nanotube film is as high as 822 MPa. More importantly, the carbon nanotube film exhibits excellent reliability. After 30 days in a strong acid/alkali and high temperature and humidity environment, the shielding performance is not affected, and the overall performance is better than other reported shielding materials.
In addition, in the preliminary work, the research team designed and prepared a series of high-efficiency, lightweight and flexible electromagnetic shielding materials, and conducted in-depth discussions on their electromagnetic shielding mechanisms. These materials include lightweight, corrosion-resistant carbon-coated silver nano Wire hybrid sponge shielding materials, MXene shielding materials with high chemical stability, MXene/Ag hybrid composite materials, graphene/cellulose aerogels and doped graphene shielding paper, etc., provide the development of new shielding materials Strong theoretical and technical support.