A self-healing material supports electronics

Materials World magazine
10 May 2019

A polymer that is transparent, stretchable and touch-sensitive can self-heal in water. Idha Valeur reports.

Jellyfish have inspired the creation of a water-resistant and self-repairing material that can be used in electronic applications, such as for soft robots in aquatic environments.

The research team in Singapore created a gel made of a fluorocarbon-based polymer with a fluorine-rich ionic liquid. When combined, they interact via ion-dipole interactions, making it able to self restore.

‘Most conductive polymer gels such as hydrogels would swell when submerged in water or dry out over time in air. What makes our material different is that it can retain its shape in both wet and dry surroundings. It works well in seawater and even in acidic or alkaline environments,’ National University of Singapore (NUS) Assistant Professor from the Department of Materials Science and Engineering, Benjamin Tee, told Materials World. According to the researchers, applications for the electric skin will include water-resistant touchscreens and potentially for sensing tension.

‘The material is also strain sensitive, and can be used for sensing tension, such as in robotic grippers for prosthetic hands or feet, or as a protective cover for digital gadgets,’ he added.

According to Tee, it is intended to replicate how human skin protects what the underneath throughout life, as it is inevitable that some damage will occur. ‘Having autonomous self-healing functions becomes important for skins. In this case, we utilised dynamic ionic bonds with polymer chains to effect the self-healing ability,’ he said.

In 2012, Tee and his research team developed the first self-healing electronic skin sensors. Since then, Tee has been developing the prototype to advance its transparency and in-water abilities.

‘The version in 2012 was less stretchable, and opaque. Our new material is transparent, stretchable and conductive,’ he said. ‘Another key difference is that it can now heal underwater.’

Going forward, the team will continue to work towards achieving real-world solutions. ‘Whether it is in the form of advanced prosthetics, robots or some other type of gadgets, I think it is important to start looking at sustainable technology growth as well,’ Tee said. ‘I believe that technology can have a tremendous positive impact for society, but we have to also be mindful of the need to make it part of a circular system, much like nature’s carbon/nitrogen cycle.’

As of today, the team has proved that the concept works and hopes to continue to explore the possibilities of the material and its range of applications. This development was a collaboration between Tee and his team, researchers from Tsinghua University, China, and the University of California Riverside, USA.