While many natural organisms – such as starfish – are capable of performing miraculous feats of self-repair, conventional materials and the devices they are made from lack this ability. The emerging field of self-healing materials could lead the emergence of robots capable of mending themselves after performing dangerous tasks, and put an end to cracked phone screens.
Previously, researchers have taken inspiration from the natural properties of squid teeth to create self-repairing clothes, and from other living tissue to create self-repairing plastic.
Now, a team of engineers at Carnegie Mellon University have produced a soft, self-repairing material which could prove valuable in wearable technologies and robotics.
The soft material is created from an elastomer containing a suspension of many liquid metal droplets. When damage is inflicted on the material, these small droplets rupture, and form connections with other surrounding droplets spontaneously. This means that even under severe mechanical damage, electrical signals can continue to be rerouted through the material. Given this useful property, the material is ideal for use in circuits, which could still function after being punctured, severed or even have material removed.
"Other research in soft electronics has resulted in materials that are elastic and deformable, but still vulnerable to mechanical damage that causes immediate electrical failure," said Professor Carmel Majidi, who is director of the Integrated Soft Materials Laboratory at Carnegie Mellon.
"The unprecedented level of functionality of our self-healing material can enable soft-matter electronics and machines to exhibit the extraordinary resilience of soft biological tissue and organisms."
Soft, conductive materials like this are particularly valuable in the field of soft robotics: a field largely concerned with building gentle robots that are pleasant for humans to interact with. According to Majidi and his colleagues, this material would be ideal for bio-inspired (biomimetic) robotics, as well as for human-machine interaction and wearable technologies. Its high electricity conductivity – which remains constant even when stretched – would make it ideal for use in power and data transmission.
"If we want to build machines that are more compatible with the human body and the natural environment, we have to start with new types of materials," said Majidi.