What if a metal object full of holes could still float on water? That idea sounds impossible, yet new research shows it can happen.
More than a century after the Titanic sank, scientists still search for better ways to stop ships and floating structures from going underwater.
A research team at the University of Rochester (URochester)has now moved closer to that goal. Scientists have created metal tubes that refuse to sink, even after heavy damage and long periods underwater.
Transforming a regular material
The research was conducted at the URochester’s Institute of Optics. The study was led by Chunlei Guo, senior scientist at the Laboratory for Laser Energetics (LLE).
The team worked with ordinary aluminum tubes. Instead of changing the shape or adding foam, the scientists focused on the inside surface of each tube.
Using a special laser technique, the group etched tiny pits and textures into the metal. These pits exist at microscopic and nanoscale levels, far too small to see with the naked eye.
This textured surface causes a powerful effect. Water cannot easily stick to it. Scientists call this property superhydrophobic, meaning extremely water repelling.
Once placed in water, the treated tube does something unusual. Water stays out of the tube instead of flowing inside. A pocket of air remains trapped within the hollow space. This trapped air keeps the tube light and buoyant.
Air weighs far less than water. As long as air stays inside, the tube avoids filling up and sinking.
This idea connects closely to nature. Diving bell spiders carry air bubbles underwater to breathe. Fire ants link together and trap air to form floating rafts during floods.
“Importantly, we added a divider to the middle of the tube so that even if you push it vertically into the water, the bubble of air remains trapped inside and the tube retains its floating ability,” says Guo.
The divider plays a key role. It helps hold the air pocket in place, even when water pushes hard from different directions.
Most floating objects fail after cracks or holes appear. Water rushes in and replaces air. That problem does not happen here. Even when the tube suffers severe damage, the superhydrophobic surface continues to repel water.
“We tested them in some really rough environments for weeks at a time and found no degradation to their buoyancy,” says Guo.
“You can poke big holes in them, and we showed that even if you severely damage the tubes with as many holes as you can punch, they still float. If you severely damage the tubes with as many holes as you can punch, they still float,” says Guo.
This result surprised many researchers. Holes usually mean failure, yet the trapped air stays protected by the water repelling surface inside the tube.
Better stability in rough water
Guo and his research group first showed superhydrophobic floating devices in 2019.
That earlier design used two flat water repelling disks sealed together. While effective in calm water, extreme tilting caused problems. At sharp angles, air could escape.
The tube design solves that issue. The cylindrical shape holds air more securely and resists movement from waves. Tests placed the tubes in rough water conditions similar to ocean environments. Weeks passed without any loss of floating ability.
This improvement makes the design more realistic for real world use.
From floating tubes to large platforms
One tube can float, but many tubes together create new possibilities. The research team connected several tubes to form rafts.
These rafts stayed stable and supported weight in laboratory tests. Tube lengths reached nearly half a meter during experiments.
Guo believes scaling up presents no major barrier. Larger versions could support heavy equipment, people, or structures. Possible uses include ships, floating platforms, buoys, and offshore structures.
A role in clean energy
The research also points toward renewable energy. Rafts made from these tubes can move with waves. That motion creates mechanical energy. Devices attached to the rafts could convert wave movement into electricity.
Wave power remains an underused renewable resource. This floating technology may help capture energy from oceans and rivers in a more durable way.
The research shows how small surface changes can create large effects. A simple metal tube, once treated, gains the ability to float against damage, time, and rough water.
The dream of safer floating structures now looks closer than ever.
Funding for the project came from the National Science Foundation (NSF), the Bill and Melinda Gates Foundation, and the Goergen Institute for Data Science and Artificial Intelligence at the University of Rochester.
The study is published in the journal Advanced Functional Materials.
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