Porous 3D Shapes Could Make Graphene 'Sponges' That Are 10 Times Stronger Than Steel
MIT researchers developed a computer model that shows the ideal structure for using graphene in the real world.
Graphene, a two-dimensional form of carbon, is stretchy and more resilient than rubber, stronger than steel and conducts electricity better than copper. But enlisting the material for real-world scenarios, like in electronic devices, cars or architectural structures, has been almost impossible. The material is super thin - exactly one atom thin - and so far, too delicate to be used to its fullest potential.
Now a team of researchers at MIT have developed a computer model that simulates fusing flakes of graphene into three-dimensional configurations. They discovered that if they shaped the two-dimensional layer of carbon atoms into a particular three-dimensional, porous form, the resulting structure would be ten times the strength of steel with just five percent of its density.
"What we've done is to realize the wish of translating these 2D materials into three-dimensional structures," Markus Buehler, the head of MIT's Department of Civil and Environmental Engineering, said in a press statement.
It turns out that other researchers had experimented with different kinds of three-dimensional shapes, but the structures always fell short in strength tests.
Buehler and his team decided to go down to the level of the atom. The computer model they made not only simulates the chemical synthesis that occurs when fusing graphene flakes together, but also allows the researchers to test the mechanical properties of the resulting shape.
After running several simulations, they found the ideal structure that exhibited the most strength: It resembles a wavy-holed block of Swiss cheese or maybe a sponge designed by Antoni Gaudi.
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"The 3D structure is composed of a continuous curved surface," team member Zhao Qin, a Civil and Environmental Engineering research scientist, told Seeker. "It's like a mosaic of graphene flakes that occupy the entire surface of the curved structure."
The continuous surface maintains the two-dimensional aspect of graphene, helping to maintaining its remarkable properties. When they used the computer model to test the structure's strength, they found that although the porous form had five percent the density of steel, it was ten times stronger.
What's more, it appeared that the strength came, not just from the graphene material, but from the geometry of the shape.
"These 3D porous graphene structures are light and very strong," Qin said.
The scientists used a 3D printer to print a representative 3D structure out of polymer resin. It's possible, Qin said, that other kinds of materials that are more common and cheaper than graphene, such as cellulose and even silk proteins, could be formed into the groovy 3D structure to improve their tensile strength.
Out in the world, the porous geometrical structure could finally turn graphene into a usable material to build lightweight and sturdy bridges or construct extremely tall skyscrapers.
Caption: A 3D-printed model shows the special three-dimensional shape scientists discovered could give graphene and other lightweight materials incredible strength.