For centuries, the oceans have carried ships, fueled trade, and supported human progress. Yet beneath the surface, an invisible enemy relentlessly attacks metal structures: corrosion. Saltwater, with its unforgiving chemistry, eats away at ships’ hulls, offshore platforms, and marine infrastructure, costing billions of dollars each year in maintenance and repair. Engineers and scientists have long sought ways to shield metal from this slow but devastating decay.
Among the most promising solutions are superhydrophobic coatings—surfaces so water-repellent that droplets bead up and roll away like tiny pearls. By minimizing contact between metal and water, these coatings can create a powerful barrier against corrosion. But while they hold incredible potential, their real-world applications have been limited. The Achilles’ heel of most superhydrophobic materials is their fragility: they scratch easily, wear down quickly, and often fail under harsh marine conditions.
Now, a team of researchers in China believes they have found a way forward—by turning a waste problem into a scientific solution.
Turning Trash into Armor
At the Institute of Oceanology, Chinese Academy of Sciences (IOCAS), Professor Zhang Binbin and his team asked a daring question: What if the answer to marine corrosion could be found in something as ordinary—and as problematic—as old tires?
Every year, the world discards millions of rubber tires, creating mountains of waste that are difficult to recycle and harmful to the environment. Left in landfills, they leach toxic chemicals; when burned, they release dangerous pollutants. Finding a sustainable way to reuse this material has long been a challenge.
Drawing inspiration from the durability of running tracks—which are made of layered rubber designed to endure pounding feet, weather extremes, and constant friction—the team envisioned using recycled tire rubber (RTR) as a protective skeleton for a new kind of coating. Instead of discarding old tires, they could be reborn as guardians of marine structures.
The result was a triple-layered superhydrophobic composite coating, with recycled rubber particles acting as an armored skeleton. Strong, elastic, and weather-resistant, this design promised to overcome the weaknesses of traditional coatings.
Resilience Under Fire
Designing a promising coating is one thing; proving its toughness is another. To test their creation, the researchers subjected it to a gauntlet of challenges that simulated the harshest real-world conditions.
The coating endured 1,200 cycles of sandpaper abrasion, 450 tape-peeling cycles, and even 1,050 grams of sand impact. Where other coatings might have worn away or lost their water-repellent properties, the recycled-rubber armor stood firm. Throughout the trials, the surface maintained its superhydrophobic nature—raindrops still rolled off effortlessly, as though the coating had just been applied.
But abrasion resistance was only part of the story. The researchers also tested how well the coating could defend metal against the slow, corrosive power of salt. Using electrochemical impedance spectroscopy, they found remarkable results: the steel substrate’s resistance to charge transfer—a key indicator of corrosion protection—increased by seven orders of magnitude, while its corrosion current density dropped by five orders of magnitude.
Even after 840 hours immersed in a 3.5% saltwater solution and 1,680 hours of exposure to marine atmosphere, the coated steel showed no signs of failure. The protection endured, suggesting that this new design offers not only immediate strength but also lasting defense.
A Win for Science and Sustainability
This achievement is more than a scientific breakthrough—it is a vision of how innovation and sustainability can go hand in hand. By repurposing waste rubber tires, the team addressed two pressing problems at once: the need for durable marine coatings and the global challenge of tire pollution.
The researchers emphasized that their RTR-armored coating is not just a laboratory curiosity. Its wear-resistance, weather-resistance, and long-term stability make it a practical candidate for real-world marine applications, from ships and docks to offshore oil platforms and wind farms.
Moreover, the use of recycled materials points to a future where industrial byproducts and environmental waste can be reimagined as resources. In this case, what once littered landfills could now protect steel from the corrosive forces of the sea.
The Broader Horizon of Superhydrophobicity
This breakthrough is part of a larger journey in material science. Superhydrophobic surfaces, inspired by nature—like the lotus leaf that repels water and dirt—have long fascinated scientists. They promise not only anti-corrosion coatings but also self-cleaning surfaces, anti-icing technology, and even medical applications.
Yet until now, the fragility of these surfaces has limited their widespread adoption. By marrying biomimicry with industrial recycling, Professor Zhang’s team has offered a blueprint for how superhydrophobic technology can leap from the lab bench to the open ocean.
A Future Shielded by Innovation
Corrosion may never be fully defeated, but with innovations like this, its impact can be dramatically reduced. Imagine fleets of ships with hulls that resist the ocean’s bite for years longer than before, offshore platforms that remain strong in saltwater storms, and renewable energy installations in the sea protected by a skin of recycled resilience.
The oceans will always test human engineering. Waves will crash, winds will tear, and salt will corrode. But with creativity, persistence, and a willingness to turn waste into innovation, humanity can rise to the challenge.
In the story of the RTR armored superhydrophobic coating, there is both science and poetry: a reminder that even discarded tires, once symbols of pollution, can be transformed into shields of protection—guardians of steel, saviors of resources, and allies in the fight against corrosion.
More information: Binbin Zhang et al, Rubber running track inspired ultra-robust superhydrophobic coating armored with recycled tire rubber (RTR) particles for sustained corrosion resistance, Chemical Engineering Journal (2025). DOI: 10.1016/j.cej.2025.167434
