Containing electromagnetic radiation generated by electronic components is an important consideration for designers of electronic equipment, but today's metal-based shielding materials also have their drawbacks. Scientists at the Swiss Federal Institute of Materials Science and Technology (EMPA) have developed a new aerogel-based material that can block multiple frequencies, forming the lightest electromagnetic shielding material they describe to date in the world .
Blocking electromagnetic radiation in electronic equipment is essential to maintain its performance, because if these fields are not isolated from the surrounding environment, it will affect signal transmission or the function of nearby electronic equipment. Engineers often use thin metal sheets to accomplish this task, but these metal sheets add extra weight to the equipment and may not necessarily be perfectly integrated with the design.
The EMPA team has been working on alternative materials, hoping to produce lighter and more plastic solutions, which allowed them to find cellulose fibers from wood. These cellulose fibers are refined to a nanometer size and combined with silver nanowires to form a lightweight porous aerogel with "excellent electromagnetic radiation shielding effect" and a density of only 1.7 per cubic centimeter Mg.
While the composition of cellulose fibers and silver nanowires produces a shielding effect, the porosity of the material also plays a role. When the electromagnetic field meets the pore, it will bounce back in the gap, generating a secondary electromagnetic field, which actually cancels out the original electromagnetic field. According to the team, this combined effect is a material that blocks almost all radiation in the 8 to 12 GHz range. At the same time, the required absorption level can be adjusted by adjusting the porosity of the material, the number and thickness of silver nanowires.
The team was able to further reduce the weight by replacing the silver nanowires with titanium carbide plates, which act like "bricks" and cellulose fibers are "mortars." The team claims that this titanium carbide cellulose aerogel combination is "the lightest electromagnetic shielding material in the world to date".
Two papers detail the research, published in "ACS Nano" and "Advanced Science".