Welcome to Karlsruhe Institute of Technology (KIT) where scientists have created a very small lattice structure that is being claimed as the smallest structure in the world. It has been created using braces and struts that measure in at under 10 micrometers in length and under 200 nanometers in diameter. The final product, 3D lattice, has a size of under 10 micrometers but claims to have more specific strength when compared to most solids.
As per the KIT team, the lattice has set a new bar for the strength to density ratios for metamaterials because of dimensions that are, when compared with metamaterials, less than by a factor of five. Metamaterials is the name given to the materials that have been made by man and exhibit properties that are not found in nature. The structure is created from glassy carbon – the form of pure carbon that features both ceramic and glassy properties along with graphite properties.
The manufacturing of the lattice began from an established 3D lithography process. The 3D lithography process is the one where the structure is hardened using computer controlled lasers in a photoresistive bath. The process can only create struts that are about 5-10 micrometers in length and 1 micrometer in diameter. The team had to then vitrify and further shrink the lattice by making use of pyrolysis.
Pyrolysis is the name given to the process where the material in question is subjected to high temperatures in the absence of oxygen. For this particular material, it was placed in a vacuum furnace and subjected it to about 900° C, thus resulting in the reorientation of the chemical bonds and eventually, only carbon was left in the lattice while other elements were removed. This carbon was unordered and in the form of glassy carbon.
Professor Oliver Kraft, co-author of the study said, “According to the results, load-bearing capacity of the lattice is very close to the theoretical limit and far above that of unstructured glassy carbon. Diamond is the only solid having a higher specific stability.”
The team’s work has been published in the journal Nature Materials.