- The new material will protect radars from bad weather impact and even bullets.
- At the beginning of the work, the authors of the study set a goal to increase the permittivity of polyethylene.
- The scientists added to it a little (only 1% by weight) multilayer carbon nanotubes in order to create such substance.
Russian physicists created an ultra-strong and transparent material for radio waves based on polyethylene and carbon nanotubes. It will protect radar from bad weather impact and even bullets. The achievement is described in a scientific article published in the journal Technical Physics.
At the beginning of the work, the authors of the study set a goal to increase the permittivity of polyethylene, so that it can be used as a coating that is radio-transparent in a given frequency range.
To do this, they decided to modify the material with nanotubes. To achieve the desired effect, the nanoparticles had to be distributed in the material so that they were evenly distributed and did not touch each other. Otherwise, the properties of polyethylene will deteriorate.
A polyethylene molecule is a long chain of identical links. Each link consists of two carbon atoms and four hydrogen atoms (C2H4).
When there are 1,500-2,000 such links in a molecule-chain, it becomes a flexible material that is used in manufacturing of plastic bags and film. However, if the length is increased dozens of times, it produces a very tough and unusually strong substance: ultra-high molecular weight polyethylene.
It can withstand not only mechanical stress, but also extremely low temperatures, high humidity and even acid. The material is versatile and has a wide range of the applications from the cutting boards, body armor, medical implants and many others that are made of the “advanced” polyethylene.
Furthermore, physicists from Krasnoyarsk and Novosibirsk decided to add a new property to this material: transparency for radio waves of a certain length. As a result, the modified polyethylene can be used to protect the antennas from the Act of God and even during combat operations.
“The most important thing is that it will pass electromagnetic waves of the required frequency, and others, on the contrary, will be extinguished. This is very important for radar equipment,” says the first author of the article Ilya Markevich from the Institute of chemistry and chemical technology of the Krasnoyarsk scientific center SB RAS.
Moreover, the scientists added to it a little (only 1% by weight) multilayer carbon nanotubes in order to create such substance. Nevertheless, for the desired effect, it was necessary to evenly distribute these nanoparticles over the thickness of the material.
To do this, the chemists used a clever method. First, they mixed both components (polyethylene and nanotubes) with a solvent. Then the resulting substance was exposed to ultrasound to mix it for an even distribution of components. Finally, the experimenters removed the solvent and compressed the material.
The resulting composite was indeed transparent to radio waves of the desired range. But in addition to this, he acquired an additional bonus. It turned out that ultrasound treatment increases the already high wear resistance of ultra-high molecular weight polyethylene by 40%.
This effect (but not radio transparency) is preserved, even if nanotubes are not added to the material.