Researchers at the University of Rochester described a way to make metal tubes that keep their buoyancy by preventing water from entering. The team used an etching process on aluminum tubes to create micro- and nano-scale pits on the interior surface; these structures render the metal superhydrophobic, so the surface repels water and stays dry. When a treated tube enters water, the superhydrophobic interior traps a stable air bubble that prevents the tube from filling and losing buoyancy.
To maintain the trapped bubble even under vertical forcing, the researchers added a divider in the middle of the tube. They compare the mechanism to natural examples such as diving bell spiders and fire ants, which use air or water-repellent bodies to stay afloat. The group first demonstrated related floating devices in 2019 with two sealed disks; the new tube simplifies the approach and improves performance in rough conditions.
Laboratory trials included tubes of varying lengths, up to almost half a meter, tested in rough environments for weeks with no measurable loss of buoyancy. The tubes also survived severe damage: even with many holes punched in them, they continued to float. Multiple tubes can be linked into rafts that could serve as the basis for ships, buoys or floating platforms. The researchers also showed that such rafts could harvest wave motion to generate electricity, and Guo says the technology could be scaled to larger sizes for load-bearing applications.
- Possible uses: ships, buoys, floating platforms
- Energy: harvest water waves to make electricity
- Robust design: resists damage and rough conditions
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.
Difficult words
- buoyancy — Ability of an object to float.
- etch — To make a surface rough by chemicals.etching
- superhydrophobic — Extremely water-repellent at very small scales.
- repel — To push away or prevent contact.repels
- trap — To capture and hold something inside.traps, trapped
- harvest — To collect energy or resources for use.
- robust — Strong and able to resist damage.
- load-bearing — Able to support weight or heavy loads.
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- What advantages do these superhydrophobic tubes have compared with traditional sealed floats? Give reasons from the article.
- What problems or challenges might appear when scaling this technology to large, load-bearing structures?
- How could harvesting wave motion with linked tubes affect coastal energy supply or local communities?
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