3D printing technologies that can swiftly produce new objects from various materials are often depicted in science fiction.
But in practice,
3D printing still has a restricted range of material kinds and qualities,
especially when printing at extremely small scales.
Researchers at Stanford have created a unique material that allows for printing at the nanoscale, producing structures that are only a small portion of the width of a human hair.
They have utilized this material to print tiny, lightweight lattices.
The researchers showed in a report that was published in Science,
that the unique material can absorb twice as much energy as conventional 3D-printed materials of a similar density.
Future satellites, drones, and microelectronics could benefit from greater lightweight protection thanks to their technology.
“Right now, there’s a lot of interest in designing different types of 3D structures for mechanical performance,” says Wendy Gu,
an assistant professor of mechanical engineering and the paper’s corresponding author.
“On top of that, we’ve developed a material that is extremely resistant to forces,
so it’s not just the 3D structure, but also the material that provides excellent protection.”
Gu and her colleagues incorporated metal nanoclusters—tiny clumps of atoms—into their printing medium to create a better material for 3D printing.
The researchers print using a technique known as two-photon lithography,
in which the printing material is hardened by a chemical reaction triggered by laser light.
They discovered that their nanoclusters were extremely effective at accelerating this reaction,
resulting in a material that was a composite of the polymer printing medium and metal.
Metal nanoclusters were successfully combined with acrylates, epoxies, and proteins, three common classes of polymers used in 3D printing.
Introducing metal nanoclusters
Furthermore,
the nanoclusters aided in the acceleration of the printing process.
Gu and her colleagues,
for example,
were able to print at a rate of 100 millimetres per second by combining nanoclusters with proteins,
which is approximately 100 times faster than had previously been achieved in nanoscale protein printing.
The researchers tested their new material with a variety of lattice structures,
prioritizing the ability to carry a heavy load in some and impact absorption in others.
All of the structures demonstrated an impressive combination of energy absorption, strength, and recoverability with the nanocluster-polymer composite –
essentially the ability to squish and spring back.
“The lattice structure is important,
what we’re showing here is that the material it’s made of is more important for performance,” Gu says.
“If you have the right materials to print with, you don’t have to worry about the exact 3D structure.”
Mimicking Nature
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 allow our bones to transfer energy without breaking (most of the time) and remain relatively lightweight.
Ideally,
3D-printed protective structures would also have multiple types of material within them,
some harder and some softer, to better disperse an impact and resist crushing.
“Since the nanoclusters can 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.”
Source: Stanford
