Discovery of unsinkable metal could build safer ships and harvest wave energy

Spiders taught scientists to make unsinkable metal

Researchers have mimicked the air-trapping tricks of diving spiders to create aluminum that stays afloat, even when pierced.

By Deni Ellis Béchard edited by Eric Sullivan

Throw a coin into a fountain and you will know what will happen. Being denser than water, metal flows – ask any child. But new research has called centuries of certainty into question.

A team from the University of Rochester etched aluminum tubes so they won’t leak, even if damaged: a trick scientists borrowed. spiders.

“You can drill big holes in it,” Chunlei Guo, a professor of optics and physics at the University of Rochester and lead author of the research, said in a study. press release. “We showed that even if you severely damage the tubes with as many holes as possible, they still float.”

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Many things in our lives repel water, for example cooking oil, a rain jacket or a rubber glove. Scientists call this property hydrophobic – from the Greek “fear of water” – but the secret to the buoyancy of metal tubes lies in greathydrophobia.

Guo’s team uses lasers to carve microscopic valleys in the aluminum that trap air: the corduroy fabric shrank until it required an electron microscope to see the ridges.

According to the press release, “the mechanism is similar to the way diving spiders trap an air bubble to stay buoyant underwater.” Spiders live almost entirely underwater but still need to breathe. Their solution is to carry their own oxygen supply. The fine hairs that cover their bodies trap air bubbles against their skin.

The metal tubes mimic these fine hairs, trapping their own air bubbles. Normally, the water would spread along the interior walls and push out the air. But when it reaches the superhydrophobic texture, it bounces back. Surface tension – the same property that causes water to bead up on a waxed car hood – prevents water from entering the tube. As a result, the air stays inside and the tubes remain buoyant.

The study, published on January 27, 2026 in Advanced functional materials, builds on Guo’s previous work on unsinkable metal design. In 2019, his lab demonstrated the concept using laser-etched discs, but in turbulent water, the discs tipped over and air escaped.

The new tubes solve this problem with an internal separator in the middle of the tube which helps trap air in a confined chamber. “Even if you push it vertically into the water, the air bubble remains trapped inside and the tube retains its ability to float,” Guo said in the same statement. The team tested the tubes in harsh conditions for weeks and “observed no degradation in their buoyancy,” he reported.

In nature, superhydrophobia is not new. Mosquito eyes have water-repellent nanostructures that keep them clear, for example. And fire ants use their waxy, water-repellent coating and textured exoskeletons to trap air; During floods, thousands of people cling together to make floating, living rafts that can survive 12 days or more.

As for humans, this isn’t our first attempt at making metal float. In 2015, researchers at New York University incorporated hollow spheres of silicon carbide into a magnesium alloy to create a metal matrix composite that is lighter than water.

But the implications of Guo’s work extend beyond the laboratory. Linked tubes could create rafts or carrier ships. Engineers may be getting closer to the dream of ships that stay afloat even when water seeps into their hulls. One surprising application concerns energy: Guo’s team demonstrated that rafts made of tubes could capture waves to produce electricity.

The tubes are currently nearly half a meter long, but Guo sees no obstacles to increasing their size. Lasers are now seven times more powerful than they were in 2019, when Guo first attempted laser-etched metal discs. “The technology,” he said in the same statement, “could easily be scaled up to larger sizes.”