Engineers have developed a metal structure that remains buoyant even when severely damaged or forced underwater, potentially paving the way for unsinkable ships and resilient offshore platforms.
Researchers at the University of Rochester have developed a process that turns ordinary aluminium tubes into “superhydrophobic” structures that trap air so effectively that they refuse to sink. The study, published in Advanced Functional Materials, suggests the technology could be scaled for use in shipping, buoys, and renewable energy harvesting.
Etching for buoyancy
The team, led by Chunlei Guo, professor of optics and physics, used a laser-etching process to create micro- and nanopits on the interior surface of aluminium tubes. This texture repels water and traps a stable bubble of air inside, preventing the tube from becoming waterlogged.
The mechanism mimics nature, functioning similarly to how diving bell spiders use their hydrophobic hairs to trap air bubbles for breathing underwater, or how fire ants form floating rafts.
To ensure the tubes remain buoyant under extreme stress, the engineers introduced a structural innovation: a central divider.
“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.
Resilience in rough seas
Unlike previous hydrophobic designs that could fail when tilted or submerged, the new tube design proved highly resilient during testing. The researchers subjected the tubes to turbulent conditions for weeks and deliberately damaged the structures to test their limits.
“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,” says Guo.
The researchers linked multiple tubes together to form rafts, demonstrating how the technology could be scaled for load-bearing applications. Beyond maritime safety, the team demonstrated that these superhydrophobic rafts could harvest energy from water waves, offering a potential new avenue for renewable power generation.
