A group of diverse scientists has created flexible fibers that possess self-healing, light-emitting, and magnetic characteristics. The innovative Scalable Hydrogel-clad Ionotronic Nickel-core Electroluminescent (SHINE) fiber is highly flexible, produces brilliant light, and has the ability to repair itself after being sliced, restoring nearly all of its original brightness. Furthermore, this fiber can be wirelessly powered and physically controlled using magnetic forces.
A group of interdisciplinary researchers from the Department of Materials Science and Engineering at the National University of Singapore (NUS) has crafted flexible fibers that are self-repairing, capable of emitting light, and exhibit magnetic features.
The SHINE fiber is bendable, generates bright visible light, and can automatically mend itself after being cut, recovering almost 100 percent of its initial brightness. It can also be wirelessly powered and manipulated with magnetic forces.
Thanks to its multiple functions packed into one fiber, it holds great promise for applications like light-emitting soft robotic fibers and interactive displays. It can even be integrated into smart textiles.
“Today, most digital information is largely transmitted using light-emitting devices. Our focus is on developing sustainable materials that emit light and exploring new formats, such as fibers, to broaden application possibilities, including in smart textiles. One way to create sustainable light-emitting devices is by making them self-healing, akin to biological tissues like skin,” explained Associate Professor Benjamin Tee, who led the research.
The team’s collaborative research with the Institute for Health Innovation & Technology (iHealthtech) at NUS was published in Nature Communications on 3 December 2024.
Multifunctional enhancements in one fiber
Light-emitting fibers are gaining attention due to their potential to enhance existing technologies across various fields like soft robotics, wearable electronics, and smart textiles. They could provide dynamic lighting, interactive displays, and optical signaling, enhancing human-robot interactions by making them more intuitive and responsive.
Nonetheless, the practical use of light-emitting fibers is often hampered by their physical fragility and the challenges of integrating multiple features in a single device without complicating it or raising energy demands.
However, the SHINE fiber developed by the NUS team tackles these issues by amalgamating light emission, self-healing abilities, and magnetic manipulation in a single scalable device. Unlike current market options, which typically lack self-repair capabilities and physical manipulation, the SHINE fiber provides a more durable, versatile, and efficient solution.
This fiber utilizes a coaxial design consisting of a nickel core for magnetic properties, a zinc sulfide-based electroluminescent layer for light production, and a hydrogel electrode for transparency. Using a scalable ion-induced gelation technique, the researchers produced fibers up to 5.5 meters in length that maintained their functionality after nearly a year of open-air exposure.
“To ensure effective visibility in bright indoor environments, a brightness level of about 300 to 500 cd/m2 is recommended,” stated Associate Professor Tee. “Our SHINE fiber boasts a maximum luminance of 1068 cd/m2, greatly surpassing the recommended threshold, which allows it to remain highly visible even in well-lit conditions.”
The hydrogel layer of the fiber can self-repair through the reformation of chemical bonds in ambient conditions, while the nickel core and electroluminescent layer regain their structural and functional effectiveness via heat-induced dipole interactions at 50 degrees Celsius.
“Most significantly, the recovery process brings back over 98 percent of the fiber’s original brightness, ensuring that it can withstand mechanical stress after being repaired,” added Associate Professor Tee. “This property encourages the reuse of damaged but self-repaired fibers, enhancing the sustainability of this technology over time.”
Additionally, the SHINE fiber’s nickel core enables magnetic manipulation, allowing the fiber to be controlled by external magnets. “This is a fascinating feature, making it applicable in dynamic light-emitting soft robotic fibers capable of navigating tight spaces, performing complex movements, and signaling in real-time,” highlighted Dr. Fu Xuemei, the paper’s first author.
Discovering new interactions between humans and robots
The SHINE fiber can be incorporated into smart textiles that produce light and self-repair after cuts, thus enhancing durability and practicality in wearable technology. With its innate magnetic properties, the fiber can operate as a soft robot, emitting light, self-healing, navigating snug spaces, and signaling visually even after being completely severed. Additionally, it can serve in interactive displays, where its magnetism facilitates dynamic changes of patterns for optical interaction and signaling in dim environments.
Looking ahead, the researchers plan to enhance the precision of magnetic manipulation to enable more intricate robotic functions. They’re also investigating the potential to integrate sensing functionalities—such as detecting temperature and humidity—into light-emitting textiles comprised entirely of SHINE fibers.
