Despite being 2D in design, researchers have found a way to 3D-print graphene into some of the strongest structures possible.
It appears that atom-thin graphene has struck again in making an astounding breakthrough, this time by taking the 2D structure and bringing it into the 3D world.
In a paper published to Materials Horizons, the Virginia Tech and Lawrence Livermore National Laboratory team revealed it had developed a way to 3D-print complex graphene objects, some of the strongest in existence.
Previously, teams had only printed graphene in 2D sheets or basic structures, but the resolution of these new 3D objects is at an order of magnitude far greater than ever before – as small as 10 microns.
This means, at least in theory, it is possible to create a graphene object of any shape or size.
With its high thermal and electrical conductivity, graphene is highly coveted in many industries, including battery development, aerospace, separation, heat management, sensors and catalysis.
The key to this breakthrough was tweaking graphene aerogel, a process where sheets of the material are separated by air-filled pores. This helps overcome the problem of packing graphene together – when this happens, it has quite poor mechanical properties.
Make anything you want
Previous 3D-printing attempts were limited to something called an extrusion process – similar to squeezing a toothpaste tube – but could only create simple objects that stacked on top of the graphene itself.
“With that technique, there’s very limited structures you can create because there’s no support and the resolution is quite limited, so you can’t get freeform factors,” said Xiaoyu Zheng of the research team.
To create the highly complex structures, the researchers had to turn to a precursor of the ‘wonder material’ called graphene oxide.
Breaking it down using ultrasound and adding light-sensitive acrylate polymers, the team used projection micro-stereolithography to create objects with the graphene oxide trapped in the long, rigid chains of acrylate polymer.
Finally, the structure would be put into a furnace to burn off the polymers and fuse the object together, leaving behind a pure and lightweight graphene aerogel.
Lead author Ryan Hensleigh added: “We can access pretty much any desired structure you want.”