Scientists have created a new type of polyurethane that can heal itself underwater, inspired by the amazing abilities of red sea stars.
This breakthrough was achieved by a research team led by Professors Zhu Jin and Chen Jing at the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences, in partnership with the Korea Advanced Institute of Science and Technology.
Their findings were published in the journal Macromolecules.
Self-healing materials are special because they can repair themselves after being damaged, which makes them last longer and remain more reliable.
Polyurethane is one of the materials that scientists have been exploring for its self-healing properties, mainly because it is easy to produce and very flexible.
However, there has always been one big challenge—water.
When polyurethane is exposed to water, the molecules interfere with its ability to self-repair, making it difficult for the material to heal underwater.
This limitation has prevented it from being widely used in underwater applications like marine robots or medical devices that are exposed to moisture.
To solve this problem, the research team took inspiration from red sea stars. These marine creatures can heal themselves quickly underwater, thanks to a biological process that involves the secretion of special enzymes.
Inspired by this natural mechanism, the researchers designed a new kind of polyurethane that can self-heal in water at room temperature.
The secret to their success lies in the material’s design. They combined two hydrophobic (water-repellent) units with a special type of dynamic bond that allows the material to reconnect and heal even when submerged. This unique structure prevents water from interfering with the healing process.
In their experiments, the researchers found that scratches on the polyurethane completely disappeared after just 12 hours underwater, with a self-healing efficiency of 98%. The material healed at a speed of 33.33 micrometers per hour, which is remarkably fast for underwater healing.
Not only does this new polyurethane heal quickly, but it also becomes strong again after the process.
In fact, it was able to hold up to 500 grams of weight without breaking after it repaired itself. The researchers also tested its biocompatibility, finding that it is safe for use in medical devices that come into contact with living tissue.
This breakthrough opens up exciting possibilities for the future.
The material could be used in underwater robots that repair themselves without human intervention or in medical implants that heal on their own after being damaged.
Inspired by the humble red sea star, this new polyurethane could change how we think about self-repairing materials, especially in challenging environments like underwater or inside the human body.
