Scientists from the University of California, Irvine, and other institutions have announced that they have architecturally designed plate-nanolattices, which are nanometer-sized carbon structures. The team says that the structures are stronger than diamonds as a ratio of strength to density. The scientists reported their success in conceptualizing and fabricating a material, consisting of closely connected, close-cell plates instead of the common cylindrical trusses common in such structures.
The team says that previous beam-based designs hadn’t been efficient in terms of mechanical properties. However, the new class of plate-nanolattices that have been created are dramatically stronger and stiffer than the best beam-nanolattices. The team says that their design has been shown to improve on the average performance of cylindrical beam-based architectures by up to 639 percent strength and by 522 percent in rigidity.
The team was able to verify their findings using a scanning electron microscope and other technologies provided by the Irvine Materials Research Institute. The team says that their achievement rests on a complex 3D laser printing process called two-photon polymerization direct laser writing. In the process, a laser is focused inside a droplet of an ultraviolet-light-sensitive liquid resin.
The material becomes solid when polymer molecules are simultaneously hit by two photons. By scanning the laser, or moving the stage in three dimensions, the technique can render periodic arrangements of cells, each consisting of assemblies of plates that are as thin as 160 nanometers. One of the innovations made by the group involves tiny holes in the plates that can be used to remove excess resin from the finished material.
The final step in the process has the lattices go through pyrolysis, when heated to 900 degrees Celsius in a vacuum for an hour. The result is a cube-shaped lattice of glassy carbon that has high-strength scientists ever thought possible such a porous material.