This month, the four-year-old Havana syndrome finally has a reasonable explanation. A new report issued by the National Academy of Sciences stated that a series of mysterious neurological diseases previously reported may be caused by directed microwave energy.

　　 Microwave radiation usually refers to electromagnetic waves with a frequency of 300 to 300,000 MHz and a wavelength of less than 1 m. It is a physical source of pollution and is not easy to detect.

　　 More than a certain amount of microwave radiation can cause harm to the human body. The specific impact is mainly on the central nervous system, which may cause headaches, dizziness, sleep problems, memory loss and so on. In addition, it will also affect the cardiovascular system and reproductive system.

　　 Microwave radiation is very widespread in life, and there is a small amount of microwave radiation in mobile phones, microwave ovens, and routers. However, since the value is extremely small, there is no need to worry about having too much impact on the body.

　　 Recently, in response to microwave radiation, scientists have developed a special fabric called "Faraday fabric", which can block almost all electromagnetic waves.

　　 This research result comes from Drexel University (Drexel University) and has been published in "Carbon" magazine.

　　 The key component of this fabric is a material called MXene, which helps protect wearable devices from interference and protect people from potentially dangerous radiation.

　　 MXenes is a conductive two-dimensional material, which has attracted more and more attention due to its application in sprayable antennas, conductive clay and fast charging battery electrodes.

　　 A few months ago, the Drexel University team described a special MXene material-titanium carbonitride (titanium carbonitride) excellent electromagnetic shielding performance.

　　 Titanium carbonitride is not only very thin (only a few atoms thick), but it absorbs signals instead of reflecting them, so it blocks electromagnetic waves in the process.

　　 In the new study, researchers have discovered a new application of MXene shielding, namely the production of fabrics that shield electromagnetic waves. They immersed a cotton and linen sample in the MXene solution and found that it could eventually block more than 99.9% of the signal.

　　 After careful observation, it seems that MXene material can stick to the fabric fibers very well due to the charge of the material. The team said that this can be made into a durable coating that does not require other pre-treatment or post-treatment processes like other conductive materials.

　　 In the long-term effectiveness test, these fabrics proved to show good performance. After two years of storage under normal conditions, the shielding effect of the sample has only a relatively small drop, between 8% and 13%.

　　Usually, electromagnetic radiation protection clothing uses a loop formed by metal fibers in the clothing to generate an induced current, and the induced current generates a reverse electromagnetic field for shielding. The metal fiber material can reflect electromagnetic waves, that is, when the aperture of the metal mesh is smaller than 1/4 of the wavelength of the electromagnetic wave, the electromagnetic wave cannot pass through the metal mesh.

This achievement provides a better choice for current electromagnetic interference shielding materials. MXene coated fabrics not only surpass the performance of commercial metal coated fabrics, but they can be sustainably produced through aqueous solutions in the form of coatings without additional processing. Or chemical additives.

The team said that these shielding fabrics can be used to protect wearable electronic products from interference without adding too much volume to them, and can also be used for those who need to venture into places with dangerous high electromagnetic fields or those who may be exposed. Personnel under strong microwave radiation make protective clothing.