Recognized as one of the strongest materials found on Earth, the semi-metal graphene is widely used for applications that require high strength, as well as thermal and electrical conductivity. Graphene is comprised of a single layer of carbon atoms that are organized into a hexagonal lattice.
While this material has been printed in the past, researchers have only been capable of doing so in 2D sheets or basic structures. Until now…
Researchers from Virginia Tech University and the Lawerence Livermore National Laboratory (LLNL) have collaborated to develop a novel 3D printing process that allows them to 3D print graphene “at a higher resolution that was an order of magnitude greater than ever printed before.”
Prior to this breakthrough development, printing stacked sheets of graphene – known as graphite – would lead to objects with lackluster mechanical properties. But this new 3D printing technique enables the separation of graphene sheets with air-filled pores, which helps to maintain the material’s strength.
“Now a designer can design three-dimensional topology comprised of interconnected graphene sheets. This new design and manufacturing freedom will lead to optimization of strength, conductivity, mass transport, strength, and weight density that are not achievable in graphene aerogels.” said Xiaoyu “Rayne” Zheng, assistant professor with the Virginia Tech Department of Mechanical Engineering in the College of Engineering and director of the Advanced Manufacturing and Metamaterials Lab.
The porous graphene structure that is produced with this method is called a graphene aerogel. It’s optimal for a variety of applications, including batteries, aerospace, separation, heat management, sensors, and catalysis.
Previous graphene 3D printing methods involved an extrusion process that was only capable of creating simple objects. Ryan Hensleigh, lead author of the study and Macromolecular Science and Engineering Ph.D. student, set out to develop this new technique during his internship at the LLNL.
These complex structures were created by crosslinking sheets of graphene oxide to form a porous hydrogel. This hydrogel is then broken down with ultrasound and fused with acrylate polymer material.
The researchers utilized a projection micro-stereolithography 3D printing process to create complex structures out of this unique graphene-polymer mix. Once the object is printed, it’s then placed into a furnace to shed the polymer, leaving behind a pure and lightweight graphene aerogel.
According to the research team, their new technique is capable of printing objects in a resolution as low as 10 microns, which they state is an order of magnitude finer than has ever been achieved with 3D printing.
“It’s a significant breakthrough compared to what’s been done. We can access pretty much any desired structure you want,” Hensleigh said.
The research findings were recently published in the journal Materials Horizons.
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