An "Ultra-Soft" Stretchable Composite Could Lead to "Imperceptible" Health-Monitoring Wearables
Stretching and compressing without damage, its creators claim this material is so soft you can't even feel it on your skin.
Researchers at the University of Missouri, the University of Nebraska Medical Center, Purdue University, the University of Illinois at Urbana-Champaign, North Caroline State University, and the National Strategic Research Institute in Omaha have developed an ultra-soft material that, they say, is ideal for comfortable wearables for long-term health monitoring.
"Our overall goal is to help improve the long-term biocompatibility and the long-lasting accuracy of wearable bioelectronics through the innovation of this fundamental porous material which has many novel properties," explains Zheng Yan, assistant professor and co-corresponding author on the paper detailing the breakthrough.
"“It is ultra-soft and ultra-stretchable, so when the device is worn on the human body it will be mechanically imperceptible to the user," Yan claims of his team's creation. "You cannot feel it, and you will likely forget about it. This is because people can feel about 20 kilopascals or more of pressure when something is stretched on their skin, and this material creates less pressure than that."
The material in question is a liquid-metal elastomer composite soft enough to feel like skin, while being stretchable and breathable. Possibly more importantly, given the team is targeting healthcare uses for the material, it's also antibacterial and antiviral — and maintains its electrical performance through repeated stretch-and-relax cycles.
"We call it a mechanical and electrical decoupling," Yan explains, "so when the material is stretched, there is only a small change in the electrical performance during human motion, and the device can still record high-quality biological signals from the human body."
The team has proven that the material can be used in electronics project, creating a light-up logo using the elastomer composite, and has developed a range of wearable prototypes including a heart monitor designed for long-term use. "The wearable system based on [our material] can perform high-fidelity ECG [electrocardiogram] and ICG [impedance cardiogram] recording even during motions," the researchers claim.
The team's work has been published in the journal Science Advances, under open-access terms.