Scientists have found a new way to structure carbon at the nanoscale, creating a structure superior to diamond in terms of strength and density.
Although the tiny carbon lattice has been made and tested in the laboratory, it is still a long way from practical use. But this new approach could help us create stronger, lighter materials in the future, which is of great interest to industries such as aerospace and aviation.
What we're talking about here are something known as nanolatic structures - porous structures like the one in the image above, made up of three-dimensional carbon struts and braces. Thanks to their unique structure, they are incredibly strong and lightweight.
Typically these nanolatics are based on a cylindrical frame (they are called beam nanolatics). But the team has now created platelet nanolatics, structures based on tiny platelets.
Based on experiments and calculations, the plate approach promises a 639% increase in strength and a 522% increase in stiffness compared to the nanostructured beam method.
To definitively test these materials in the lab, the researchers used a complex laser 3D printing process called two-photon direct laser writing polymerization, which essentially uses carefully controlled chemical reactions inside a laser beam to etch shapes on the smallest scales.
Using a liquid resin that is sensitive to ultraviolet light, the process emits photons at the resin to turn it into a solid polymer of a specific shape. Additional steps are then required to remove excess resin and heat the structure to secure it in place.
What the scientists have achieved here actually approaches the maximum theoretical stiffness and strength of this type of material—the limits known as the Hashin-Shtrikman and Suquet upper limits.
As confirmed by scanning electron microscopy, these are the first real experiments to show that the theoretical strength limits can be achieved, although we are still a long way from being able to produce this material on a larger scale.
In fact, part of the material's strength lies in its tiny size: when such objects are compressed to 100 nanometers—a thousand times smaller than the thickness of a human hair—the pores and cracks in them become increasingly smaller, reducing potential defects.
As for how these nanolattics might ultimately be used, they will certainly be of interest to the aerospace industry—the combination of strength and low density makes them ideal for aircraft and spacecraft.