Engineers at the University of Rochester have developed a laser-etching process that makes ordinary aluminium tubes “unsinkable”, even after prolonged submersion or heavy damage. The team, led by optics professor Chunlei Guo, treated the inside of the tubes to create micro- and nano-scale pits that make the surface superhydrophobic, causing it to repel water. When placed in water, the treated surface traps a stable pocket of air inside the tube, keeping it buoyant, similar to how diving bell spiders hold air bubbles underwater and how fire ants form floating rafts.

To improve stability, the researchers added a divider inside the tube so the air pocket remains trapped even when the tube is pushed vertically into water. In tests over weeks in rough conditions, the tubes retained buoyancy and continued to float even when punctured with multiple holes. Linked together, the tubes could form rafts for ships, buoys, platforms, or wave-energy devices.