Engineers from MIT, Caltech, and ETH Zürich published a new study investigating “nanoarchitected” materials designed using precisely patterned nanoscale structures. The researchers believe the material could be promising for lightweight armor, protective coatings, blast shields, and other impact-resistant materials. The ultralight material is fabricated using nanometer-scale carbon struts making the material very tough and giving it strong mechanical robustness.
The material was tested by shooting it with microparticles at supersonic speeds. They discovered the material prevented the miniature particles from tearing through it despite being thinner than the width of a human hair. According to the team, compared with steel, Kevlar, aluminum, and other impact-resistant materials of comparable weight, the new material is more efficient at absorbing impacts. Lead researcher Carlos Portela says the same amount of mass of the new material would be more efficient stopping a projectile than the same mass of Kevlar.
If the new material was produced on a large scale, it could be designed as lighter and tougher than other commonly used materials. Depending on how they are arranged, the nanometer-scale structures the nanoarchitected material is patterned with can have unique properties such as exceptional lightness and resilience. Portela says researchers only know the response of these materials in a slow-deformation regime. A lot of practical use is hypothesized to be in real-world applications where nothing deforms slowly.
His team wanted to study the materials under conditions of faster deformation, such as with high-velocity impacts. At Caltech, they fabricated a nanoarchitected material using two-photon lithography. That technique uses a high-powered laser to solidify microscopic structures in a photosensitive resin. Researchers constructed a repeating pattern known as a tetrakaidecahedron.
After patterning that structure, researchers washed the leftover resin away. Next, they placed the structure in a high-temperature vacuum furnace to convert the polymer into carbon resulting in an ultralight and architected carbon material. To test the material under extreme deformation, the team performed a microparticle impact experiment at MIT using laser-induced particle impact tests. For this test, 14-micron-wide silicon oxide particles were used. The team adjusted the particles to velocities from 40 to 1100 meters per second, noting that anything supersonic is above 340 meters per second. The experiments show the material can absorb a lot of energy with the particles unable to pass through the material.