Stretchable Sensing with Liquid Metal-Infused Electronic Fibers

An Innovative Breakthrough in Electronic Fiber Technology

A team of researchers at EPFL has successfully developed a fiber-based electronic sensor capable of retaining functionality even when stretched to over 10 times its original length. This groundbreaking device shows great potential for applications in smart textiles, physical rehabilitation devices, and soft robotics.

Revolutionizing Electronic Fibers with Liquid Metal

Utilizing a mixture of indium and gallium known as liquid metal, researchers at the Laboratory of Photonic Materials and Fiber Devices (FIMAP) in EPFL’s School of Engineering have paved the way for the development of electronic fibers for wearable technology and robotic sensors. Liquid metals, such as the one used in this study, are non-toxic, remain in liquid form at room temperature, and offer immense potential for various electronic applications.

Despite the challenges posed by processing liquid metals, the FIMAP team managed to overcome these obstacles by employing a technique called thermal drawing, typically utilized in the production of fiber optics. This innovative approach has enabled the creation of fiber sensors with finely tuned electronic properties, making them ideal for smart textiles designed for sports and health monitoring.

Engineering Stretchable, Sensitive Fibers

The thermal drawing process involves creating a macroscopic version of the electronic fiber, known as a preform, which contains carefully arranged liquid metal components in a 3D pattern. By heating and stretching the preform, fibers of varying diameters are produced while retaining the original 3D pattern. This unique pattern allows for precise control over the active (electrically conductive) and inactive (insulating) areas of each fiber.

Experiments have demonstrated that these fibers maintain high sensitivity even when stretched to extreme lengths, showcasing a significant advantage over existing methods that struggle to balance electrical performance with stretchability and ease of processing.

Practical Applications and Future Prospects

In a remarkable proof-of-concept, researchers integrated the electronic fibers into a soft knee brace and monitored its performance during various physical activities. The brace accurately tracked the wearer’s knee movements and gait, showcasing the potential for monitoring other joints as well. The scalability of this technique opens doors for integrating these fibers into textiles on a large scale, enabling the creation of wearables, soft prostheses, and sensors for robotic applications.