Engineers from the National University of Singapore (NUS) have developed a new super-flexible, self-healing and highly conductive material suitable for stretchable electronic circuitry. According to the team, the breakthrough could significantly improve the performance of wearable technologies, soft robotics, smart devices and more.
The newly engineered material, dubbed the Bilayer Liquid-Solid Conductor (BiLiSC), can stretch up to a remarkable 22 times its original length without sustaining a significant drop in its electrical conductivity. This electrical-mechano property, which hasn’t been achieved before, enhances the comfort and effectiveness of the human–device interface and opens up a wide array of opportunities for use in healthcare wearables and other applications.
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‘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 in BiLiSC allows these devices to withstand large deformation and even self-heal to ensure electronic and functional integrity.’
BiLiSC consists of two layers. The first layer is a self-assembled pure liquid metal that can provide high conductivity even under high strain, reducing energy loss during power transmission and signal loss during signal transmission.
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The second layer is a composite material that contains liquid metal microparticles. This layer is able to repair itself after breakage – when a crack or tear occurs, the liquid metal in the microparticles can flow into the gap, enabling the material to heal itself almost instantaneously while retaining its high conductivity.
To ensure that the innovation is commercially viable, the team found a way to fabricate BiLiSC in a highly scalable and cost-efficient manner.
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The team demonstrated that BiLiSC can be made into a variety of electrical components of wearable electronics, including pressure sensors, interconnections, wearable heaters and wearable antennas for wireless communication.
In laboratory experiments, a robotic arm using BiLiSC interconnections was quicker at detecting and responding to minute changes in pressure compared to another interconnection made with a non-BiLiSC material. In addition, the bending and twisting motion of the robotic arm didn’t impede the transmission of signals from the sensor to the signal-processing unit.
Following the successful demonstration of BiLiSC, the NUS team is now working on material innovation and process fabrication. They’re looking to engineer an improved version of BiLiS that could be printed directly without needing a template. This would reduce cost and improve the precision of fabrication.
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The research has been published in Advanced Materials.