A good quite chaotic, as it happens. When the researchers tested the strength of each lattice, the Type IV Bouligand structure absorbed 20 times the energy of Type I. “This kind of microstructure makes this kind of composite very tough,” said Qiming Wang, engineer at the University of Southern California. , co-author of a new paper detailing the findings in the journal Advanced materials“If you have a crack, that crack will propagate in the squiggle pattern to dissipate the energy in the material.” In fact, the material absorbs more energy than natural nacre (nacre), which gives some shells their strength, and also beats existing artificial materials, Wang and colleagues say.
Just as the mantis shrimp’s hammer absorbs the energy of its thrusts without breaking, so do the materials developed with this new method. For possible applications, Wang says to think of bulletproof vests, which have to dissipate the energy of a bullet. Calcium carbonate is also fairly lightweight, so scientists may be able to grow harder panels for planes or even skins for robots, too, says Wang.
“This is a way for me to produce in the future, and I’m not alone in saying that,” said Pablo Zavattieri, a civil engineer from Purdue University, who was not involved in this study. In traditional manufacturing, defects can creep in. Nature, on the other hand, has developed the miraculous Bouligand structure in the mantis shrimp hammer over millions of years, and it is a pattern that can be replicated with a simple grid and bacterial bath. “Nature is flawless that way,” says Zavattieri. “Nature is a 3D printer.”
Another thing that makes this bacteria-built material special is its ability to regenerate. Like, what if instead of building roads, we grew them? “When we have damage, you just bring in bacteria, and it can make it grow back,” Wang says. “These structures are very tough, very strong and can potentially repair themselves.”
The researchers aren’t quite there yet – they let the bacteria grow minerals under controlled conditions in the lab, and even then it was only in small amounts. Upscaling for road construction would bring additional technical challenges; for example obtaining the correct ratio between scaffolding and paving material. But Zavattieri is actually already busy with 3D printing of concrete. “I don’t think it’s super crazy,” he says. “We can have robots fully print the classic scaffold, leave the bacteria there and then let them grow the material for 10 days.”
So maybe the brazen bashing of the mantis shrimp could one day help fix America’s broken infrastructure, instead of just breaking thumbs.
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