Using a process similar to chemical pulping, he strips the lignin—which gives wood its brownish color—from the veneer pieces. Once the lignin has been stripped from the wood and replaced with a polymer, a one-millimeter strip of Berglund’s composite is 85% transparent—a number that Berglund thinks he will be able to increase over time.
The advantage of transparent wood over something like glass is that it has all the strength of opaque lumber—but still lets in light. Berglund’s process, then, could be used to create everything from transparent wood structures to load-bearing windows that never crack or shatter. “We’re getting a lot of interest from architects, who want to bring more light into their buildings,”. It’s also as biodegradable and environmentally friendly as regular wood. We even imagines that his composite could be used to create entirely new types of sustainable solar panels, made out of wood instead of chemically treated glass.
Right now, a lot of work to do before his composite shows up in, say, a new transparent Ikea line. Although suitable for mass-production, he’s unsure how affordable it will be to scale his technique. Still, wood is one of the strongest, toughest, hardest materials there is, and we just figured out how to make it practically invisible. Just imagine what architects and designers will do with transparent wood when they finally get their hands on it.
A team of researchers at MIT has designed one of the strongest lightweight materials known, by compressing and fusing flakes of graphene, a two-dimensional form of carbon. The new material, a sponge-like configuration with a density of just 5 percent, can have a strength 10 times that of steel.
In its two-dimensional form, graphene is thought to be the strongest of all known materials. But researchers until now have had a hard time translating that two-dimensional strength into useful three-dimensional materials.
The new findings show that the crucial aspect of the new 3-D forms has more to do with their unusual geometrical configuration than with the material itself, which suggests that similar strong, lightweight materials could be made from a variety of materials by creating similar geometric features.
The findings are being reported today in the journal Science Advances, in a paper by Markus Buehler, the head of MIT’s Department of Civil and Environmental Engineering (CEE) and the McAfee Professor of Engineering; Zhao Qin, a CEE research scientist; Gang Seob Jung, a graduate student; and Min Jeong Kang MEng ’16, a recent graduate.
The unusual geometric shapes that graphene naturally forms under heat and pressure look something like a Nerf ball — round, but full of holes. These shapes, known as gyroids, are so complex that “actually making them using conventional manufacturing methods is probably impossible,” Buehler says. The team used 3-D-printed models of the structure, enlarged to thousands of times their natural size, for testing purposes.
For actual synthesis, the researchers say, one possibility is to use the polymer or metal particles as templates, coat them with graphene by chemical vapor deposit before heat and pressure treatments, and then chemically or physically remove the polymer or metal phases to leave 3-D graphene in the gyroid form. For this, the computational model given in the current study provides a guideline to evaluate the mechanical quality of the synthesis output.
The same geometry could even be applied to large-scale structural materials, they suggest. For example, concrete for a structure such as a bridge might be made with this porous geometry, providing comparable strength with a fraction of the weight. This approach would have the additional benefit of providing good insulation because of the large amount of enclosed airspace within it.
Because the shape is riddled with very tiny pore spaces, the material might also find application in some filtration systems, for either water or chemical processing. The mathematical descriptions derived by this group could facilitate the development of a variety of applications, the researchers say.