Leather-like material paves the way for consistent, wireless and battery-free wearable devices

Wearable technologies are revolutionizing healthcare, enabling new forms of personalized monitoring, diagnosis and care. These technologies, including smartwatches, fitness trackers and portable medical devices, aim to collect data on various health indicators such as heart rate, physical activity, sleep patterns and even blood oxygen levels. This data can be used to monitor patients in real time, providing valuable information that can help with early disease detection, management of chronic diseases and overall health maintenance.

According to industry reports, the smart clothing market is expected to grow significantly in the coming years, with health and fitness applications accounting for the largest share in terms of end-use.

Now, the breakthrough is paving the way for the next generation of battery-free wearable devices – a revolutionary material that mimics the elasticity of skin while maintaining signal strength in electronics.

Scientists from Rice University and Hanyang University created this revolutionary material by embedding clusters of high-dielectric ceramic nanoparticles in a flexible polymer. This ingenious design not only mimics the elasticity and movement of skin, but also adapts its electrical properties. This regulation counteracts the negative impact of traffic on connected electronics, minimizing energy loss and heat dissipation.

The team combined simulations and experiments to design a material that deforms smoothly like skin and changes the way electrical charges are distributed within it when stretched to stabilize radio frequency communications, explained Raudel Avila, an assistant professor of mechanical engineering at Rice and lead author on the study.

Electronic devices use radio frequency (RF) components, such as antennas, to send and receive electromagnetic waves. In mobile and flexible systems, the challenge is to ensure that the frequency does not change so that communication remains stable. Any change or transformation in the shape of these RF components causes a shift in frequency, which means you will experience signal interference, Dr. Avila explained.

To solve this problem, researchers focused on the high-dielectric nanocomposite substrate on which the wireless device sits, rather than the electrodes and structure that have traditionally been the focus.

Scientists envision broad applications of this technology, including portable medical devices, soft robotics and high-performance antennas. To test its effectiveness, they built several stretchable wireless devices – an antenna, a coil and a transmission line – and tested them on a newly developed substrate and a standard elastomer (no nanoparticles).

“We believe our technology can be applied to various fields such as portable medical devices, soft robotics, and high-performance thin and light antennas,” said Abdul Basir, a former Hanyang researcher and now a PhD student at the University of Tampere in Finland.

“We have demonstrated that our system supports stable wireless communication over distances of up to 30 meters (~98 feet) even under heavy load. With a standard substrate, the system completely loses connectivity,” Avila said.

Moreover, the novel material can improve wireless connectivity across a variety of wearable platforms designed for different body parts and sizes. Scientists have created bionic headbands for the head, knee, arm and wrist to monitor a variety of health data, including brain wave activity (EEG), muscle activity (EMG), joint movement and body temperature. The headband, which spans 30% of a toddler’s head and 50% of an adult’s head, effectively transmitted real-time EEG data over a distance of 30 meters.

“As wearable devices evolve and influence the way society interacts with technology, particularly in the context of health technology, the design and development of high-performance, stretchable electronic devices becomes critical for stable wireless connectivity,” Dr. Avila concluded.

This breakthrough paves the way for a future where portable health devices seamlessly integrate with our bodies, constantly monitoring our health and transmitting data without compromising signal strength or battery life.

A paper describing materials, manufacturing and design strategies was published in the journal Nature. The authors of the study are Sun Hong Kim, Abdul Basir, Raudel Avila, Jaeman Lim, Seong Woo Hong, Geonoh Choe, Joo Hwan Shin, Jin Hee Hwang, Sun Young Park, Jiho Joo, Chanmi Lee, Jaehon Choi, Byunghum Lee, Kwang-Seong Choi, Sungmook Jung, Tae-il Kim, Hyoungsuk Yoo and Yei Hwan Jung.