New nanoscale 3D-printing material could offer better structural protection for satellites, drones and microelectronics

Engineers at Stanford University have designed a new material for nanoscale 3D printing that is able to absorb twice as much energy as other similarly dense materials. Nanoscale printing creates structures that are a fraction of the diameter of a human hair and can print minuscule materials that are both strong and light. The results of the work are published in Science.

The research was supported through multiple research grants from the U.S. National Science Foundation and through NSF support for the Stanford Site of the National Nanotechnology Coordinated Infrastructure. Additionally, team members David Doan and Melody Wang were supported by an NSF Graduate Research Program Fellowship.

The researchers demonstrated that the new material can absorb twice as much energy as other 3D-printed materials of a comparable density. In the future, their invention could be used to create better lightweight protection for fragile pieces of satellites, drones and microelectronics.

"There's a lot of interest right now in designing different types of 3D structures for mechanical performance," says Wendy Gu, a Stanford mechanical engineer and a corresponding author on the paper. "What we've done on top of that is develop a material that is really good at resisting forces, so it's not just the 3D structure, but also the material that provides very good protection."

The researchers were able to combine metal nanoclusters with several common classes of polymers that are used in 3D printing. The nanoclusters helped to speed up the printing process. By combining the nanoclusters with proteins, for example, Gu and her colleagues were able to print at a rate of 100 millimeters per second, which is about 100 times faster than what had previously been achieved in nanoscale protein printing.

With the nanocluster-polymer composite, all the structures demonstrated an impressive combination of energy absorption, strength and recoverability — essentially the ability to squish and spring back.

In some ways, Gu and her colleagues are trying to mimic what nature has already perfected. Bone, for example, gets its resilience from the combination of a hard exterior, nanoscale porosity, and small amounts of soft material. This combination of a 3D structure and multiple, well-designed materials allows bones to transfer energy without breaking while remaining relatively lightweight.

"Since the nanoclusters are able to polymerize these different classes of chemicals, we may be able to use them to print multiple materials in one structure," Gu says. "That's one thing we'd like to aim for."