Metal tubes that do not sink ^{CEFR B1}

Researchers at the University of Rochester published the method in Advanced Functional Materials and developed etched aluminum tubes that do not sink. The team used an etching process to create micro- and nano-scale pits on the interior surface. These tiny structures make the metal superhydrophobic, so the surface repels water and remains dry.

When a treated tube enters water, the superhydrophobic interior traps a stable bubble of air inside. The trapped air prevents the tube from filling with water and losing buoyancy. The team compared the effect to natural examples such as diving bell spiders and fire ants. Chunlei Guo, a professor of optics and of physics and a senior scientist at URochester’s Laboratory for Laser Energetics, said they added a divider in the middle so the air stays trapped even if the tube is pushed vertically. Guo and colleagues first built superhydrophobic floating devices in 2019 using two sealed disks; the new tube design simplifies the concept and improves performance in rough conditions.

In lab trials the team tested tubes of varying lengths, up to almost half a meter, and found them resilient in rough environments for weeks. Guo reported that tubes can survive severe damage: even after many punched holes they still float. Multiple tubes can be linked into rafts for ships, buoys or floating platforms, and the researchers demonstrated that such rafts could harvest water waves to generate electricity. The project received support from the National Science Foundation, the Bill and Melinda Gates Foundation, and URochester’s Goergen Institute for Data Science and Artificial Intelligence.