Australia claims to have developed a new kind of self-repairing paint that significantly slows the rusting of steel. Researchers at the University of Queensland have created a powder that, when mixed with water-based paint, enables the paint to repair itself and block rust. In lab tests, steel coated with this paint loses only 37 nanometers per year to corrosion. However, real-world testing, such as on a bridge, is still pending. Every seven years or so, the Eiffel Tower is covered in scaffolding as workers strip off old paint, treat the iron beams, and apply tens of tons of new paint. This is a multi-month effort that costs millions of dollars. Without this upkeep, rust would gradually destroy the structure. Similar challenges exist for bridges, power line towers, ship hulls, and other metal structures, where steel constantly battles against oxidation. The innovation involves nanocontainers that detect the first crack in the paint. Traditional anticorrosion paints eventually degrade, and even a small scratch can expose steel to moisture and oxygen, leading to rust. Asep Nugraha, a researcher at the Australian Institute of Bioengineering and Nanotechnology at the University of Queensland, has developed particles in powder form that can be added to water-based polyurethane paint. These particles act like tiny reservoirs containing a rust inhibitor known as benzotriazole. Encased in metal-organic frameworks—porous crystalline structures—the inhibitor remains trapped until a crack appears. At that point, the drop in pH caused by the beginning of corrosion triggers the release of the inhibitor directly at the damaged site. Benzotriazole then binds to the steel, forming a thin protective film that prevents oxidation. Laboratory electrochemical tests show that the protected steel corrodes only 37 nanometers per year, compared to 25,000 nanometers per year for many high-performance coatings currently available. This represents an improvement of more than 600 times, according to the university. Another test involved intentionally scratching steel plates and submerging them in salt water for 14 days. With the most effective formulation, no rust formed around the scratch. Kwang Keat Leong, a doctoral student, explored using nanocellulose—plant fibers extracted from biomass—to grow the metal-organic crystals, increasing inhibitor storage and protection up to five times. These results, published in the journal Small Science, are still lab-based. The 600-fold improvement figure compares experimental results with industry claims, but real-world testing on a bridge is still needed. If proven effective, the paint could reduce the number of construction sites and lower pollution. Corrosion is costly, requiring regular stripping and repainting of structures. A more durable coating would reduce the frequency of these large-scale projects and the waste they generate. Asep Nugraha envisions a single coat that could protect Brisbane's Story Bridge for over a century. However, he cautions that the paint will not last forever, only significantly longer than current options. From an environmental perspective, the paint starts with water-based ingredients, which emit fewer volatile organic compounds. Unlike traditional paints, the inhibitor does not continuously leak with rain. However, benzotriazole, the rust inhibitor, is a persistent molecule that requires monitoring for its environmental impact. The next step is to conduct pilot-scale tests, with the goal of bringing a commercial product to market within five years. Before that, the team must reduce manufacturing costs and ensure the paint remains stable in cans and in spray guns used on construction sites.