It is now possible to 3D print air. Or rather, something even lighter. An international team of scientists has developed a technique to 3D print graphene aerogel, crowned the world’s lightest material in 2013. Weighing in at 7.5 times lighter than air, one square meter of this aerogel has a mass of just 160 grams. Flexible, conductive, elastic, ultra-absorbent… the properties of this solid gas, often called “frozen smoke” seem to be infinite. One of its potential applications could be to decontaminate the ocean from hydrocarbons, as one gram of graphene aerogel can absorb up to 900 times its weight in oil. However, initial results of experiments with graphene-based aerogel show that its porous structure is very irregular, and therefore not adaptable on an industrial scale.
But researchers from the University at Buffalo in New York State and Kansas State University have developed a process to 3D print each piece uniformly. Practically speaking, the technique is the same for making ordinary aerogel. As graphene by itself is a two-dimensional, one-atom-thick layer of pure carbon, several layers must literally be freeze-dried and stacked up to produce aerogel.
The printer head stacks layers of graphene oxide mixed with water onto a surface cooled to -25°C, where each layer freezes instantly. Once printed, the entire piece is dipped in liquid nitrogen, then dried.
Demonstration video of printing process:
In 2015 in California, another team of researchers at the Lawrence Livermore National Laboratory had already succeeded in 3D printing a more organized structure, especially applied to nanoelectronics.