UPDATE (Feb. 17, 2026): This story has been updated to note Meza’s work with the NSF I-Corps program and CoMotion Innovation Gap Fund.
Biology is full of architecture. Materials like wood, crab shells and bone all contain microscopic structures such as layers, lattices, cells and interwoven fibers. Those structures give natural materials an ideal combination of lightness and toughness, and they鈥檝e inspired engineers to build artificial materials with similar properties. But how those tiny architectures lead to such tough materials is something of a mystery.
In 2019, , assistant professor of mechanical engineering, set up the at the 91爆料 to tease out the mechanical secrets of structures that are as small as 100 nanometers, which is about the size of a virus. He arrived with an ambitious plan to build a new generation of nanomaterials, but soon discovered that the field was missing a fundamental understanding of toughness at tiny scales.
鈥淲e had to go back to basics,鈥� Meza said.聽
In the years since, Meza and his team have flipped the script on nanomaterial toughness. They鈥檙e applying what they鈥檝e learned to new kinds of bespoke materials, though along the way they鈥檙e still surprised by tiny structures behaving in ways they theoretically shouldn鈥檛.
Meza spoke with 91爆料 News about his strange and surprising journey into the nano realm.
What questions did you establish your lab to tackle?
Lucas Meza: Very broadly, we’re trying to design better materials, but not by introducing new material chemistries. Instead, we use architecture. This is something humans have done throughout history 鈥� think of woven textiles and fabrics, or straw-reinforced mud bricks. These are 鈥渁rchitected materials,鈥� where the structure of materials allows us to control useful properties like strength, toughness and flexibility.聽
The thing that I was particularly interested in was introducing architecture at the nanoscale. What if, instead of building a wall with bricks, we could use nanoplatelets? Or instead of making fabrics with yarn, we could use nanofibers? How would those properties change?
Engineers have found that nanomaterials are stronger, more flaw resistant and more deformable. The challenge is: How do you actually do something with them? We need to build them into large-scale materials in a way that preserves their unique nanoscale properties.聽
What material properties are you most interested in?
LM: We鈥檙e using architecture to tinker with a few interrelated properties. The first is a material鈥檚 strength, which is how much stress it can take before it permanently deforms. The second is ductility, which is how much a material can stretch before it breaks. Those two features sort of combine to determine a material鈥檚 toughness, which is the total amount of energy you have to put into a material to break it.
To give a couple of opposing examples: A ceramic plate is strong, meaning it can take a lot of stress, but it has very low ductility, meaning it barely deforms before breaking. So overall, it鈥檚 not a very tough material. Conversely, a rubber band is not strong at all 鈥� you can bend and stretch it with very little stress. But, it鈥檚 extremely ductile 鈥� it can stretch to many times its original dimensions without snapping. So as a result, rubber is very tough.
Credit: 91爆料 (left) and Envato (right).
Toughness is a particularly interesting property to study because there’s no limit on how tough a material can be. There are very hard limits on how strong and how stiff a material can be, and you can use architecture to optimize them, but you can’t exceed the properties of the base material. On the other hand, you can use architecture to improve the overall toughness of a material.聽
Nature has already created a lot of really interesting micro- and nano-structures. Every natural material has to be porous to transport nutrients, and on top of that we see things like lattices in some bone and in sea sponges; shells all have layered architectures; wood and bone are fiber composites; and all of this happens at the micro- and nanoscale.聽
There had to be a reason that nature was making these architectural motifs at the micro and nanoscale, and I had a strong hunch that it had to do with toughness.聽
What has your lab learned about toughness at the small scale?
LM: Initially, we learned a surprising amount about what we 诲颈诲苍鈥檛 know. My thought in getting into this work was that people know enough about fracture mechanics 鈥� how things break and why 鈥� so we can just dive into making really complicated architectures and studying their toughness, like l made by my former doctoral student, . We realized the scientific community has some big gaps in their understanding of fracture toughness. So instead, we had to go simple 鈥� basically we pulled and pushed and broke a lot of small things to understand what gives a material ductility and toughness.
We learned that all material behavior centers around something called a 鈥減lastic zone size.鈥� Basically, when you pull on a part that has a crack, a little ball of energy builds up right at the tip of that crack. That energy ball grows as you add more stress, and at a certain point it shoots through the sample and causes a break. The size of the ball at its breaking point is the material鈥檚 plastic zone size, and it鈥檚 different for every material.聽
We realized that what makes a material ductile or not . If a material is smaller than its plastic zone size, that ball of energy can鈥檛 grow big enough to cause the crack to grow, so instead it spreads outward and the material bends.聽
The four material samples in this video are all the same size, but structural differences at the nanoscale produce different levels of ductility. In each example, the cyan color represents the sample鈥檚 plastic zone size. In less ductile samples, the cyan-colored area remains small and the material snaps, whereas in more ductile samples, the cyan area spreads out and the material stretches. Credit: Dwivedi et. al/Journal of the Mechanics and Physics of Solids
This is the key for how to use architecture to cheat and get more ductility out of a material. If you take a brittle material and make a nanoscale lattice or foam out of it, . The new tougher 鈥渁rchitected material鈥� can also have a larger plastic zone size, sometimes as much as 100 times larger, meaning it is likely to be ductile as well. This is why things like fabrics and meshes can be really hard to tear.聽
How are you applying what you鈥檙e learning to real-world materials?
LM: We鈥檙e building lots of our material architectures painstakingly at the small scale using resources like the and the 91爆料 . That 鈥渂ottom-up鈥� approach 鈥� building things one nanofeature at a time 鈥� gives us lots of control over the building blocks we鈥檙e playing with, but it鈥檚 a real challenge to scale.
The 鈥渢op-down鈥� approach, where you let physics and kinetics just self-assemble things for you, is much easier. One example is 鈥渟olid state foaming鈥�, a technique my colleague has been working on for decades. Basically, you take a thermoplastic material 鈥� something that melts when you heat it up 鈥� throw it in a chamber with high pressure carbon dioxide so it saturates the sample, then heat it up so that dissolved gas forms tiny bubbles in the material. With this process we have less control over the precise architecture 鈥� it鈥檚 a random foam 鈥� but by controlling the amount of dissolved gas we can easily control the size of the bubbles. Those materials turned out to be super tough! My doctoral student has , where we show they could even be tougher than the material they were made from. This goes against everything we knew about normal foam fracture processes.聽
A plastic nanofoam material created by Kush Dwivedi, a doctoral student in Meza鈥檚 lab, seen at 2,500x, 12,000x and 35,000x magnifications. Credit: Dwivedi et. al/Journal of the Mechanics and Physics of Solids.
I鈥檓 currently pursuing an earlier-stage commercialization effort to use tiny foams as a filtration material for biomedical applications. We can make nanoporous filter materials 鈥� think of the reverse osmosis system that might be under your sink 鈥� but we can do it without using any of the harsh chemical processes that are currently used. We’ve been able to explore this avenue thanks to our participation in the program, which then enabled us to get a award.
I also recently got an NSF CAREER grant to study fracture in architected materials, and we鈥檙e exploring ways to make tougher sustainable and biodegradable materials. Think of the last time you used a biodegradable fork that broke off in your food. Materials like wood are actually great alternatives for this, but we鈥檙e trying to figure out how to do it without cutting down a tree or harvesting bamboo.聽
For more information contact Meza at lmeza@uw.edu.