Cambridge University team develops self-healing material made of salt and gelatine

A team of experts at the University of Cambridge, UK, has developed a 3D printed material that can self-heal and biodegrade, and sense tension, temperature and humidity, Phys reported on February 18. The new study was published in the journal NPG Asia Materials.

Soft-sensing technology could help transform robotics, tactile interfaces, wearable electronics, and more. However, most soft sensing technology is not durable and consumes a lot of energy.

Expert David Hardman at the University of Cambridge's Faculty of Engineering and colleagues have developed new self-healing materials that could be used to make prosthetic arms and soft robots. The material can sense when damaged, take the necessary steps to temporarily heal, and then resume work without human intervention.

"We've been working on self-healing materials for several years. However, now we're looking for faster and cheaper ways to build self-healing robots," said Dr. Thomas George-Thuruthel at the Faculty of Engineering at the University of Science and Technology. University of Cambridge, study co-author, said.

Older versions of the robot needed to be heated to heal, but the team is developing new materials that can heal themselves at room temperature, making them more useful in real-world applications.

"We started with a cheap, biodegradable and biocompatible gelatine-based stretchy material. We ran various tests to incorporate the sensors into the material by adding many conductive components," Hardman said.

The team discovered that the sensor contains sodium chloride salt instead of carbon ink, which helps to create materials with desired properties. The salt is soluble in water-filled hydrogels, providing a favorable pathway for ion conduction or ion movement. When measuring the resistance of 3D printed materials, the team found that changes in tension lead to a series of reactions that can be used to calculate the deformation of the material. The addition of salt also helps the material become more elastic.

Self-healing materials are cheap and easy to fabricate, requiring only 3D printing or molding. They are very durable and stable for a long time, and are made from safe, common materials. "This is a really good material in terms of how cheap and easy it is to make. We can make a robot entirely out of gelatine and print the sensors wherever it's needed," said George-Thuruthel.