Session: 04-26-01: Advanced Material Innovations in Wearable Biomedical Devices and Structures

Paper Number: 150196

150196 - Radiative Cooling Smart Textiles With Integrated Sensing for Adaptive Thermoregulation 

Increasingly erratic and capricious weather in recent years has presented a great challenge for personal health, as it entails drastic temperature fluctuations that are difficult to cope with. Many human diseases have been linked to symptoms of abnormal body temperature regulations. For example, 60 – 70% of Americans with diabetes have an impaired ability to adjust to rises in temperature, which can cause a dangerous increase in body temperature in record-breaking high temperatures. Therefore, given the growing health risk posed by climate change, it has drawn more attention to advancing personalized health monitoring and thermal management technologies.

On one hand, smart wearable technologies, along with the advances in artificial intelligence (AI) and the internet of things (IoT), have the potential to make a profound impact on our daily lives. They can enable a range of applications to improve personal health and performance, such as personalized healthcare, soft robotics, electronic skin and human-machine interface. However, previous development of smart wearables tends to focus on sensing and monitoring the bio-signals of human body. Existing wearable technologies are deficient in the requisite function for personal thermal management under different temperature conditions. Moreover, many of the previously reported wearable thermoregulation devices, such as thermoelectrics, electrochromics and phase change materials, have the disadvantages of bulky and heavy configurations, poor breathability, or difficulty in scalable manufacturing.

Passive radiative cooling and heating, on the other hand, has recently emerged as a new strategy for personal thermal management without any energy cost. This approach utilizes the selective control of radiative heat transfer by tailoring the nano- and micro-scale structure of materials. In the case of radiative heating, it has been shown that nanostructured metallic coatings and MXene materials can passively warm up the human body, due to their low infrared emissivity that can block the dissipation of thermal radiation to the surrounding environment. Despite promising progress, the previously reported radiative cooling and heating textiles lack intelligent and adaptive capabilities to quickly detect and respond to dynamic variations in the physiological status of wearers or the ambient temperature caused by imperceptible environmental factors such as sunlight, wind, and humidity under climate change.

In this work, we develop a thermally adaptive smart textile (TAST) which incorporates passive radiative cooling structures into smart wearables with seamlessly integrated sensing capabilities at the fiber level to enable intelligent, efficient, and adaptive thermoregulation. We achieve TAST using a coaxial extrusion method to create hierarchically structured core-sheath fibers comprised of a conductive metal core and a porous polymer composite sheath. Woven from these core-sheath fibers, TAST forms a network of capacitive sensors that can detect the spatial distribution of pressure or sweat on the textile. TAST also exhibits passive radiative cooling and active joule heating effects, owing to the spectrally selective sheath and conductive core of fibers, respectively. We further demonstrate the adaptive thermoregulation capability of TAST to maintain the skin temperature within the thermal comfort range of human body under various conditions by integrating its radiative cooling, joule heating, and capacitive sensing functions using a closed-loop feedback control system. We envision that TAST will have significant impact on the development of smart wearable thermoregulation technologies to improve human health and societal well-being.

Presenting Author: Yoon Young Choi University of Illinois Urbana-Champaign

Presenting Author Biography: Yoon Young Choi has a background in materials science and engineering. He is currently a graduate student in the Department of Mechanical Science and Engineering at UIUC. Before joining UIUC, he worked as a research assistant at Yonsei University in South Korea, where he specialized in flexible sensors and wearables. His current research focuses on adaptive personal thermal management using passive radiative cooling materials and sensor applications.

Authors:

Yoon Young Choi University of Illinois Urbana-Champaign
Kai Zhou University of Illinois Urbana-Champaign
Ho Kun Woo University of Illinois Urbana-Champaign
Diya Patel University of Illinois Urbana-Champaign
Md Salauddin University of Illinois Urbana-Champaign
Lili Cai University of Illinois Urbana-Champaign