Researchers at the Massachusetts Institute of Technology (MIT) have developed a new graphene material that is one of the strongest in the world while also being lightweight in form.
The new graphene material is 10-times stronger than steel with only 5% of its density.
MIT researchers have designed the lightweight material by taking small flakes of graphene, previously considered one of the strongest forms of material in the world, and compressing and fusing them into a mesh-like structure that not only retains the material’s strength but the graphene remains porous.
The small flakes of graphene were compressed through a combination of heat and pressure; with this process producing a super strong, stable ‘coral-shaped’ structure with an enormous surface area in proportion to its volume.
The new material was made in the MIT labs using a high-resolution, multi-material 3-D printer. It was then mechanically tested for its tensile and compression properties and its mechanical response under loading measured. The results showed that the simulations created through MIT research team’s theoretical models matched closely with the results from the live experiments.
3D graphene a game changer
The new graphene material solves the age old problem in that while graphene in its 2D form was thought to be one of the strongest of all known materials, previous researchers had a hard time translating that 2D strength into useful 3D materials.
While two-dimensional materials such as graphene were extremely strong, because of their thinness they could not be used as 3D materials to create large structures such as buildings.
The new material addresses this problem by retaining this strength in a 3D object, paving the way for their use in creating large structures.
These findings were recently reported in a paper – The mechanics and design of a lightweight three-dimensional graphene assembly – written by the head of MIT’s Department of Civil and Environmental Engineering (CEE) Markus Buehler, as well as CEE research scientist Zhao Qin, graduate student Gang Seob Jung, and recent graduate Min Jeong Kang Meng.
Buehler highlighted the fact that the new material could be a game changer.
“They (2D materials) are not very useful for making 3D materials that could used in vehicles, buildings or devices,” he said. “What we’ve done is to realise the wish of translating these 2-D materials into three-dimensional structures.”
Potential applications for new graphene material
Buhler said the new material developed by researchers at MIT could have a number of potential uses for objects that require both extreme strength while also being light in weight.
These things include the new material being applied to large-scale structural materials using the geometry discovered by the MIT research team.
Concrete for a large-scale structure such as a bridge or building might be made with this porous geometry, with the new 3-D material providing the compatible strength needed with only a fraction of the weight.
The new material might also be used in some filtration systems for water or chemical processing, due to its shape featuring many tiny pore spaces.
Style over substance
However, while the graphene material has been shown to be very strong, the new findings by the MIT research team show that the crucial aspect of the new 3D forms has more to do with their unusual geometrical configuration than with the material itself.
This suggests that similar strong and lightweight materials to that of graphene could be made from a variety of materials by creating similar geometric features.
“You could either use the real graphene material or use the geometry we discovered with other materials, like polymers or metals,” he said. “You can replace the material itself with anything, the geometry is the dominant factor. It’s something that has the potential to transfer to many things.”
However, while other research teams had hinted at the possibility of other lightweight but strong structures, they had failed to achieve this hypothetical ambition in laboratory testing.
By fusing graphene into a porous 3-D-form, the MIT team have solved the mystery of transferring such a strong 2D material into a lightweight 3D object, with the key to its development achieved by analysing the material’s behaviour down to the level of individual atoms within the structure, producing a mathematical framework that closely matches experimental observations.
Professor of Engineering at Brown University, Huajian Gao, said the MIT research resulting in the new 3-D form of graphene was inspiring.
“This is an inspiring study on the mechanics of 3D graphene assembly,” he said. “The combination of computational modeling with 3D-printing-based experiments used in this paper is a powerful new approach in engineering research.”
“It is impressive to see the scaling laws initially derived from nanoscale simulations resurface in macroscale experiments under the help of 3D printing. This work shows a promising direction of bringing the strength of 2D materials and the power of material architecture design together.”
The MIT research which developed the new 3D material was supported by the Office of Naval Research, the Department of Defense Multidisciplinary University Research Institute, and the BASF-North American Center for Research on Advanced Materials.