Science & Technology, Singapore (Commonwealth Union) – The possibility of a revolutionary material with exceptional properties: it can stretch up to 22 times its original length and heal cracks almost instantly. To picture a stretchable and robust sensor patch designed to monitor the rehabilitation progress of patients with elbow or knee injuries, or envision an unbreakable, dependable wearable device capable of measuring a runner’s cardiac activities during training to prevent life-threatening injuries. These breakthroughs in wearable technology often face limitations due to the rigid and damage-prone electronic circuits that power these intelligent devices.
Researchers at the National University of Singapore (NUS) have recently introduced an innovative material known as the Bilayer Liquid-Solid Conductor (BiLiSC). This material is exceptionally flexible, self-healing, and highly conductive, making it ideal for use in stretchable electronic circuitry. This remarkable development has the potential to significantly enhance the performance of wearable technologies, soft robotics, smart devices, and more.
BiLiSC exhibits a unique electrical-mechanical property, allowing it to stretch up to an astonishing 22 times its original length without experiencing a significant reduction in electrical conductivity. This property not only enhances the comfort and efficiency of the human-device interface but also opens up a wide range of opportunities for its application in healthcare wearables and various other fields.
Professor Lim Chwee Teck, Director of the NUS Institute for Health Innovation & Technology as well as leader of the research team, says “We developed this technology in response to the need for circuitry with robust performance, functionality and yet ‘unbreakable’ for next-generation wearable, robotic and smart devices. The liquid metal circuitry using BiLiSC allows these devices to withstand large deformation and even self-heal to ensure electronic and functional integrity.” Professor Lim along with the team who arefrom the Department of Biomedical Engineering under the NUS College of Design and Engineering as well.
Researchers indicated that BiLiSC represents an exciting technological advancement, particularly suited for integration into wearable devices, which must accommodate the body’s diverse shapes and movements.
This innovative material comprises two distinct layers. The first layer consists of a self-assembled pure liquid metal, capable of maintaining high conductivity even under significant strain. This property minimizes energy loss during power transmission and reduces signal loss during data transmission.
The second layer is a composite material containing liquid metal microparticles, uniquely equipped with self-repairing capabilities. When cracks or tears occur, the liquid metal within these microparticles can flow into the damaged areas, enabling almost instantaneous self-healing while retaining its high conductivity.
To ensure the commercial viability of this innovation, the NUS team has devised a highly scalable and cost-efficient method for producing BiLiSC.
This groundbreaking technology, featured in the November 2022 issue of Advanced Materials, demonstrates exceptional performance and multifunctionality. The NUS team has successfully crafted various electrical components for wearable electronics using BiLiSC, including pressure sensors, interconnections, wearable heaters, and antennas for wireless communication.
In laboratory experiments, a robotic arm equipped with BiLiSC interconnections exhibited superior sensitivity in detecting minute changes in pressure. Additionally, the bending and twisting motions of the robotic arm did not impede signal transmission from the sensor to the signal processing unit, a marked improvement compared to interconnections made from non-BiLiSC materials.
Researchers are moving forward by building upon the successful demonstration of BiLiSC, the NUS team is currently focused on advancing material innovation and refining the fabrication process. Their goal is to develop an enhanced iteration of BiLiSC that can be directly printed without the necessity of using a template. This advancement is expected to bring about cost reductions and significantly enhance the precision of BiLiSC fabrication.
In recent years with the improvement in technology and greater data analytical methods, a variety of different researchers have found many new ways of advancing existing components and materials.
