Novel Liquid-Metal Material Paves Way for Super Flexible, Self-Healing Wearables

Researchers from the National University of Singapore (NUS, Singapore) have engineered a unique material known as the Bilayer Liquid-Solid Conductor (BiLiSC). This material can stretch up to an astonishing 22 times its initial length while maintaining its electrical conductivity. This groundbreaking electrical-mechano property has never been achieved before and promises to increase the comfort and effectiveness of the human-device interface. This makes BiLiSC highly suitable for wearable technology, taking into account the body's shape and diverse movements.

BiLiSC is comprised of two different layers. The first layer is composed of a self-assembled liquid metal that retains high conductivity even when stretched, minimizing energy and signal loss during transmission. The second layer is a composite material containing liquid metal microparticles that allow it to self-repair after breakage. If the material breaks or cracks, the liquid metal from the microparticles flows into the gap, enabling nearly instantaneous self-healing and retention of high conductivity. For commercial feasibility, the NUS team has also found an efficient and scalable way to manufacture BiLiSC.

To showcase BiLiSC's potential, the NUS researchers created various electrical components for wearable electronics, such as pressure sensors, interconnections, wearable heaters, and wearable antennas for wireless communication. During lab tests, a robotic arm equipped with BiLiSC was more responsive to slight changes in pressure and maintained signal transmission even during bending and twisting movements, outperforming another arm with non-BiLiSC materials. The NUS team is now focusing on further material improvements and process enhancements. They aim to develop an advanced version of BiLiSC that can be printed directly without a template, cutting down on costs and increasing precision in fabricating.

“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,” said Professor Lim Chwee Teck, Director of the NUS Institute for Health Innovation & Technology and leader of the research team. “The liquid metal circuitry using BiLiSC allows these devices to withstand large deformation and even self-heal to ensure electronic and functional integrity.”

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