Researchers develop self-healing, flexible fibres

The Scalable Hydrogel-clad Ionotronic Nickel-core Electroluminescent (SHINE) fibre is a cutting-edge material that is bendable, emits highly visible light, and can self-repair after being severed, recovering nearly 100% of its original brightness. Additionally, it can be powered wirelessly and manipulated physically using magnetic forces.

This multifunctional device offers potential applications in soft robotics, interactive displays, and smart textiles. It represents a significant leap forward in light-emitting fibres, combining durability, functionality, and sustainability.

Associate Professor Benjamin Tee, the lead researcher on the project, commented: “Most digital information today is transmitted largely through light-emissive devices. We are very interested in developing sustainable materials that can emit light and explore new form factors, such as fibres, that could extend application scenarios, for example, smart textiles. One way to engineer sustainable light-emitting devices is to make them self-healable, just like biological tissues such as skin.”

The team conducted its research in collaboration with the Institute for Health Innovation & Technology (iHealthtech) at NUS, publishing their findings in Nature Communications on 3rd December 2024.

Multifunctional fibre for diverse applications

The SHINE fibre addresses key challenges associated with existing light-emitting fibres, such as physical fragility and difficulty in integrating multiple functionalities. By combining light emission, self-healing, and magnetic actuation, it offers a durable and efficient alternative to traditional materials.

The fibre features a coaxial design, integrating:

• A nickel core for magnetic responsiveness
• A zinc sulphide-based electroluminescent layer for light emission
• A hydrogel electrode for transparency and self-healing

Using a scalable ion-induced gelation process, the team fabricated fibres up to 5.5 metres long that maintained their functionality even after a year of open-air storage.

Associate Professor Tee highlighted the device’s visibility in challenging lighting conditions: “To ensure clear visibility in bright indoor lighting conditions, a luminance of at least 300 to 500 cd/m² is typically recommended. Our SHINE fibre has a record luminance of 1,068 cd/m², comfortably exceeding the threshold, making it highly visible even in well-lit indoor environments.”

The hydrogel layer enables chemical bond reformation under ambient conditions, while heat-induced dipole interactions at 50°C restore the fibre’s structural and functional integrity.

“More importantly, the recovery process restores over 98% of the fibre’s original brightness, ensuring it can endure mechanical stresses post-repair,” added Assoc Prof Tee. “This capability supports the reuse of damaged and subsequently self-repaired fibres, making the invention much more sustainable in the long term.”

Enabling human-robot interaction

The SHINE fibre’s magnetic properties, enabled by its nickel core, allow it to be manipulated using external magnets. Dr Fu Xuemei, the study’s first author, explained its implications: “This is an interesting property as it enables applications like light-emitting soft robotic fibres capable of manoeuvring tight spaces, performing complicated motions and signalling optically in real-time.”

The fibre can be integrated into smart textiles that self-heal after being cut, adding durability and functionality to wearable technology. Its ability to emit light, self-heal, and navigate confined spaces offers new possibilities for robotics and interactive displays.

Future developments

Looking ahead, the team plans to enhance the precision of the fibre’s magnetic actuation to enable more complex robotic movements. They are also exploring the integration of sensing capabilities, such as temperature and humidity detection, into light-emitting textiles made from SHINE fibres.