Designing various 3D structures for mechanical performance is currently a hot topic. But in reality, 3D printing is still limited in the properties and materials available for use, especially when printing on a very small scale.
Stanford scientists have developed a new material for nanoscale printing. They also used the newly created material to print tiny grids that are both strong and light.
Unlike materials of similar density, this nanoscale 3D printing material can absorb twice as much energy. Moreover, it is highly resistant to forces, so not only the 3D structure but also the material provides very good protection. In the future, it is expected to be used to create better lightweight protection for vulnerable parts of satellites, drones and microelectronics.
To design this new material, scientists used metal nanoclusters — tiny clumps of atoms — in their printing medium, known as two-photon lithography. The print material is cured in this medium by a chemical reaction initiated by laser light. These nanoclusters proved to be good at eliciting this response. Thus, it leads to the formation of a material that is a composite of the polymer pressure medium and metal.
Wendy Gu, an assistant professor of mechanical engineering and a corresponding author on the paper, said: “The nanoclusters have excellent properties for capturing the laser light and then converting it into a chemical reaction. And they can do this with different classes of polymers, so they are even more versatile than I expected.”
Scientists combined proteins, acrylates and epoxies – a few popular polymers in 3D printing – with metal nanoclusters. The nanoclusters also helped speed up the printing process. For example, scientists were able to print at a speed of 100 millimeters per second using the nanoclusters and proteins, about 100 times faster than previously possible with nanoscale protein printing.
The ability to support a great deal of weight in some and the ability to withstand an impact in others were prioritized as the scientists tested their new material with different lattice configurations. All of the structures with the nanocluster polymer composite showed a fantastic mix of energy absorption, strength and recoverability – or, to put it another way, the ability to crush and bounce back.
gu said, “The grid structure certainly matters, but we’re showing here that if the material it’s made of is optimized, it’s more important for performance. You don’t have to worry about what the 3D structure is exactly if you have the right materials to print with.”
- Qi Li et al. Mechanical nanolattices imprinted with nanocluster-based photoresists. Science. DOI: 10.1126/science.abo6997