Reviewed by Lexie CornerDec 6 2024
An interdisciplinary team of researchers from the Department of Materials Science and Engineering at the College of Design and Engineering, National University of Singapore (NUS), has created flexible fibers with self-healing, light-emitting, and magnetic capabilities. The research, carried out in collaboration with the Institute for Health Innovation & Technology (iHealthtech) at NUS, was published in Nature Communications.
Developed by NUS researchers – Assoc. Prof. Benjamin Tee (right), Dr. Fu Xuemei (center), and Dr. Wan Guanxiang (left) – the multifunctional, flexible SHINE fiber can self-heal after physical damage and emit highly visible light. The versatile fiber can be powered wirelessly and manipulated physically using magnetic forces. Image Credit: National University of Singapore
The Scalable Hydrogel-clad Ionotronic Nickel-core Electroluminescent (SHINE) fiber is flexible, emits visible light, and can self-repair after being severed, restoring most of its initial brightness. It supports wireless power and can be manipulated using magnetic forces.
With its combination of features, the fiber has potential applications in light-emitting soft robotics, interactive displays, and integration into smart textiles.
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 fibers, 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.
Benjamin Tee, Associate Professor, National University of Singapore
Benjamin Tee is the lead researcher for this study.
Multifunctional Innovation in a Single Device
Light-emitting fibers are of interest for their potential applications in fields such as soft robotics, wearable electronics, and smart textiles. They enable features like dynamic lighting, interactive displays, and optical signaling, offering flexibility and adaptability to improve human-robot interactions.
However, their adoption is limited by physical fragility and the difficulty of integrating multiple functionalities into a single device without increasing complexity or energy consumption.
The SHINE fiber developed by the NUS research team overcomes these limitations by integrating light emission, self-healing, and magnetic actuation into a single, scalable device. Unlike conventional light-emitting fibers available on the market, which lack self-repair capabilities and physical manipulability, the SHINE fiber provides a more durable, efficient, and versatile solution.
The fiber features a coaxial design, incorporating a nickel core for magnetic responsiveness, a zinc sulfide-based electroluminescent layer for light emission, and a hydrogel electrode for transparency. Through a scalable ion-induced gelation process, the team successfully fabricated fibers up to 5.5 m in length, which retained their functionality even after nearly a year of open-air storage.
To ensure clear visibility in bright indoor lighting conditions, a luminance of at least 300 to 500 cd/m2 is typically recommended. Our SHINE fiber has a record luminance of 1068 cd/m2, comfortably exceeding the threshold, making it highly visible even in well-lit indoor environments.
Benjamin Tee, Associate Professor, National University of Singapore
The fiber's hydrogel layer achieves self-healing by reforming chemical bonds under ambient conditions, while the nickel core and electroluminescent layer restore structural and functional integrity through heat-induced dipole interactions at 50 ºC.
More importantly, the recovery process restores over 98 % of the fiber’s original brightness, ensuring it can endure mechanical stresses post-repair. This capability supports the reuse of damaged and subsequently self-repaired fibers, making the invention much more sustainable in the long term.
Benjamin Tee, Associate Professor, National University of Singapore
The SHINE fiber also incorporates magnetic actuation facilitated by its nickel core, enabling it to be controlled using external magnets.
“This is an interesting property as it enables applications like light-emitting soft robotic fibers capable of maneuvering tight spaces, performing complicated motions, and signaling optically in real-time,” said Dr. Fu Xuemei, the first author of the study.
Unraveling New Human-Robot Interactions
The SHINE fiber can be incorporated into smart textiles that emit light and self-heal after being cut, improving the durability and functionality of wearable technology.
Its magnetic actuation allows it to function as a soft robot, emitting light, self-healing, navigating confined spaces, and providing optical signaling even after severance. The fiber is also suitable for interactive displays, where its magnetic properties enable pattern changes and optical signaling in low-light environments.
Future work includes improving the precision of its magnetic actuation for advanced robotic applications and exploring the integration of sensing capabilities, such as temperature and humidity detection, into textiles made entirely of SHINE fibers.
Journal Reference:
Fu, X., et al. (2024) Self-healing actuatable electroluminescent fibres. Nature Communications. doi.org/10.1038/s41467-024-53955-2.