Greater than 100 years after the sinking of the Titanic, the concept of ships that can’t sink continues to motivate engineers. Researchers on the University of Rochester’s Institute of Optics have now taken a major step toward that long-standing goal. They’ve developed a method that makes unusual metal tubes unsinkable — meaning the tubes stay afloat no matter how long they continue to be underwater or how much damage they sustain.
How Trapped Air Prevents Sinking
When a treated tube is placed in water, its water-repelling interior captures a stable pocket of air inside. This trapped air keeps water from filling the tube, which prevents it from becoming heavy and sinking. The method resembles natural strategies seen in diving bell spiders, which carry air bubbles underwater, and in fire ants, which form floating rafts using their water-resistant bodies.
“Importantly, we added a divider to the center of the tube in order that even when you push it vertically into the water, the bubble of air stays trapped inside and the tube retains its floating ability,” says Guo.
Improved Stability in Rough Conditions
Guo’s research group first demonstrated superhydrophobic floating devices in 2019. That earlier design relied on two water-repelling disks sealed together to create buoyancy. While effective, the disks could lose their ability to drift when tilted at extreme angles. The newer tube-based design simplifies the structure and offers much greater stability, especially in turbulent environments just like ocean conditions.
“We tested them in some really rough environments for weeks at a time and located no degradation to their buoyancy,” says Guo. “You’ll be able to poke big holes in them, and we showed that even when you severely damage the tubes with as many holes as you’ll be able to punch, they still float.”
From Floating Rafts to Renewable Energy
The researchers showed that multiple tubes may be connected to form rafts, which could function the inspiration for ships, buoys, or floating platforms. In laboratory tests, the team experimented with tubes of various lengths, reaching nearly half a meter. Guo says the design may be scaled as much as sizes large enough to support heavy loads.
Beyond transportation and infrastructure, the team also demonstrated that rafts constructed from superhydrophobic tubes could capture energy from moving water. This capability suggests a possible role for the technology in generating electricity from waves, adding a renewable energy application to its list of possibilities.
This project was supported by the National Science Foundation, the Bill and Melinda Gates Foundation, and URochester’s Goergen Institute for Data Science and Artificial Intelligence.