In its 2D form, graphene (a thin layer of pure carbon atoms) is 200 times stronger than steel, is the thinnest material on earth (1 million times thinner than human hair) and is the world’s most conductive material.
Until now, researchers haven’t been able to create continuously fused 3D materials with graphene, retaining its unique characteristics.
“The most amazing thing we’ve discovered is that we created a bulk material made of carbon, and it’s a continuous, connected structure,” MIT research scientist Zhao Qin told Global News. “Previously people have proposed many different ways to put graphene together to form a 3D structure, but those building blocks weren’t covalently connected. They were still relatively weak.”
By calculating the behaviour of graphene down to its individual atoms, a group of researchers at MIT’s Department of Civil and Environmental Engineering was able to fuse graphene flakes in a unique gyroid shape, maintaining much of its strength while also making the nano-scale material porous.
“By fusing those graphene flakes together we really have the capability to maximize the usage of the mechanics of every single graphene building block,” said Qin. “We are also able to tune the mechanical properties. So we can use that building block to reach different designs for many different engineering applications.”
The most applicable takeaway from this study is the geometric design (inspired by elements in nature such as coral and butterfly wings) which the researchers say can be transferred to other materials.
“The geometry is very important in governing the mechanics. We might be able to use cheaper materials like concrete and metal and use the similar geometry to design very strong, stiff and lightweight materials,” said Qin.
The team conducted tensile and compression tests on their design by using both computer simulations and a high-resolution 3D printer with polymer fibre.
In one computer simulation, one design sample had only five per cent density of steel but displayed 10 times the strength.
Qin said this design isn’t meant to replace steel because the metal has its own unique properties. But some drawbacks to it are that it erodes over time and requires a large carbon footprint to produce, making it an environmental burden.
Applications for this geometric design range from aircraft design, infrastructure and filtration systems.
The researchers said their next steps are to expand their study to design new printing techniques for other materials in a real-life scale, which can be used in more engineering applications.