PolyU scholars pioneer smart and sustainable personal cooling technologies to address global extreme heat
The Hong Kong Polytechnic University
image:
Prof. Dahua Shou, Limin Endowed Young Scholar in Advanced Textiles Technologies, Associate Professor of the PolyU School of Fashion and Textiles, Associate Director of the Research Centre of Textiles for Future Fashion, and Associate Director of the PolyU–Xingguo Technology and Innovation Research Institute, has published a peer-reviewed paper in Science, offering new insights into sustainable personal cooling using advanced textiles and intelligent wearables.
view moreCredit: © 2025 Research and Innovation Office, The Hong Kong Polytechnic University. All Rights Reserved.
Global warming poses a growing threat to human health and work performance. Currently, about 3.6 billion people worldwide live in areas highly susceptible to climate change. From 2000 to 2019, more than 480,000 heat-related deaths occurred globally each year. Extreme heat also impairs focus and productivity and worsens mood by elevating stress hormones and disrupting sleep. In response to the increasing frequency of heat waves, The Hong Kong Polytechnic University (PolyU) scholars are developing next-generation personal cooling solutions that push the limits of conventional clothing and promote sustainability.
Prof. Dahua SHOU, Limin Endowed Young Scholar in Advanced Textiles Technologies, Associate Professor of the PolyU School of Fashion and Textiles, Associate Director of the Research Centre of Textiles for Future Fashion, and Associate Director of the PolyU-Xingguo Technology and Innovation Research Institute, has published a peer-reviewed paper in Science, offering new insights into sustainable personal cooling using advanced textiles and intelligent wearables.
Smart technologies, especially intelligent wearables and AI, can be key to sustainable personal cooling. Prof. Dahua Shou said, “According to the World Meteorological Organisation, there is an 80% chance that at least one year between 2025 and 2029 will be the hottest on record, making personal cooling increasingly vital for well‑being, health and productivity. We have been creating intelligent, superhero‑like garments that provide on‑demand adaptive cooling and clinician‑like health monitoring to help address the challenge of extreme heat.”
By integrating the four cooling mechanisms of radiation, conduction, convection and evaporation, this stand‑alone perspective outlines strategies to adaptively regulate body heat and moisture in dynamically changing real‑world settings. The paper also presents an AI‑driven, closed‑loop framework that connects sensing, prediction, and actuation to deliver personalised, energy-efficient cooling, with a scalable and recyclable design that supports public health, workplace safety, and performance.
Sustainable personal cooling is evolving from the use of passive fabrics to the integration of smart systems. Notably, spectrum‑selective textiles effectively release mid‑infrared body heat while blocking external solar and urban heat gain. Thermal insulation is being engineered with conduction-tunable fillers, while ventilative and evaporative cooling is boosted by moisture-responsive fibres. Lightweight wearables, such as variable emittance devices, and electrocaloric and thermoelectric modules paired with flexible solar and on-body energy storage, enable active and controllable cooling. These emerging technologies strategically employ model-selective cooling and incorporate human‑centered design for comfort, durability, washability, and low weight, expanding comfort zones and reducing dependence on air conditioning.
Despite promising progress, key challenges in personal cooling remain. Sweating helps cool the body, but limited sweat management increases fabric weight and cling, while reducing permeability and radiative cooling efficiency, especially during heavy perspiration. Real-time adaptive thermoregulation, which responds to changing environments and individual physiology while ensuring comfort and safety, is ideal but difficult to achieve.
Prof. Dahua Shou said, “We also need interdisciplinary integration across textiles, thermodynamics, flexible electronics, and AI, along with scalable, recyclable manufacturing that balances sustainability, wearability, fashion, and performance. Standardised, user‑centric metrics, such as cooling power per watt, thermal sensation, and user acceptance, are essential for fair comparison and adoption.”
Prof. Shou and his research team are tackling extreme heat with various innovative technologies. iActive™ intelligent sportswear uses low‑voltage-driven artificial “sweat glands” and a root‑like liquid network mapped to sweat zones to quickly eject perspiration as droplets, reducing weight and cling, keeping the skin dry, and removing sweat up to three times faster than peak human sweating.
Omni‑Cool‑Dry™ is a breathable skin‑like fabric that routes sweat directionally while providing spectrum‑selective cooling. By reflecting solar and ground radiation and emitting mid‑infrared body heat, it helps keep wearers cool and dry even under the sun, lowering skin temperature by about 5°C compared to conventional fabrics.
For hot workplaces, thermo‑adaptive Soft Robotic Clothing embeds temperature‑responsive soft actuators that expand to thicken fabric and trap still air, solving the problem of “one‑level” thermal insulation. Thermal resistance varies from 0.23 to 0.48 K·m²/W, keeping the inner surface 10°C cooler than conventional insulating garments even when the exterior temperature reaches 120°C.
SweatMD is an all‑textile, non-invasive wearable that channels fresh sweat through a nature‑inspired microfluidic network and uses skin‑friendly sensing yarns to track biomarkers like glucose and potassium. It delivers real‑time, molecular‑level health insights such as indicators of fatigue and dehydration to a smartphone.
Collectively, these innovations form an AI‑ready ecosystem: sensors quantify physiology, models predict cooling demand, and intelligent clothing actuates targeted responses. Integrating textile sensors, fiber‑based coolers, and on‑body energy harvesters has the potential to enable self‑sustained cooling.
Spanning everyday wear, as well as sports, and protective gear, these innovations bridge the gap between fundamental research and real-world applications to address global challenges. PolyU translational research institutes across Mainland cities and interdisciplinary research centres, such as the PolyU-Xingguo Technology and Innovation Research Institute and the Research Centre of Textiles for Future Fashion, allows the University’s scholars to tap into these cities’ diverse application scenarios and collaborate with leading enterprises to accelerate the transformation and scalable deployment of scientific research achievements.
These research innovations earned the Gold Medal with Congratulations of the Jury (2025) and a Gold Medal (2024) at the Geneva Invention Exhibition, as well as the TechConnect Global Innovation Award. Prof. Shou also received The Fiber Society’s Distinguished Achievement Award, a prestigious honour awarded annually to a single scholar worldwide.
Journal
Science
Article Title
Sustainable personal cooling in a warming world
iActive™ intelligent sportswear uses low voltage-driven artificial “sweat glands” and a root like liquid network mapped to sweat zones to quickly eject perspiration as droplets, reducing weight and cling, keeping the skin dry, and removing sweat up to 3-time faster than peak human sweating.
Omni Cool Dry™ is a breathable skin like fabric that routes sweat directionally while providing spectrum selective cooling. By reflecting solar and ground radiation and emitting mid infrared body heat, it helps keep wearers cool and dry even under the sun, lowering skin temperature by about 5°C.
SweatMD is an all‑textile, non-invasive wearable that channels fresh sweat through a nature‑inspired microfluidic network and uses skin‑friendly sensing yarns to track biomarkers like glucose and potassium. It delivers real‑time, molecular‑level health insights to a smartphone, such as indicators of fatigue and dehydration.
Wear smart, stay cool
Credit
© 2025 Research and Innovation Office, The Hong Kong Polytechnic University. All Rights Reserved.
Radiative cooling materials for extreme environmental applications
Shanghai Jiao Tong University Journal Cente
image:
- Heat exchange mechanisms for enhancing cooling performance and environmental tolerance are elucidated.
- Challenges in extreme environments, along with the corresponding anti-environmental radiative cooling materials and micro-nano structures, are reviewed.
- Valuable insights into enhancing the next generation of radiative cooling for extreme environmental applications are discussed.
Credit: Jianing Xu, Wei Xie, Hexiang Han, Chengyu Xiao, Jing Li, Yifan Zhang, Shaowen Chen, Binyuan Zhao, Di Zhang, Han Zhou.
As global temperatures rise and extreme weather events become more frequent, the demand for advanced thermal management technologies has never been more urgent. Researchers from Shanghai Jiao Tong University, led by Prof. Han Zhou and Prof. Di Zhang, have published a comprehensive review on radiative cooling materials designed for extreme environments, offering a roadmap for next-generation cooling solutions that operate efficiently in the harshest conditions on Earth—and beyond.
Why Radiative Cooling Matters in Extreme Environments
Radiative cooling is a passive thermal management strategy that allows surfaces to dissipate heat by emitting infrared radiation directly into space, without consuming energy. In extreme environments—such as deserts, high-altitude aircraft, or outer space—traditional cooling systems often fail due to high temperatures, intense UV radiation, or lack of atmosphere.
This review highlights how micro- and nano-structured materials can be engineered to selectively emit and reflect thermal radiation, enabling efficient cooling even under intense solar irradiance, high humidity, or vacuum conditions.
Key Innovations and Material Strategies
The review systematically explores four major environmental categories:
- Terrestrial Dwelling Environments
Materials must resist UV, microbes, flames, and pollution while maintaining high mid-infrared (MIR) emissivity in the 8–13 μm atmospheric window.- Example: A polyoxymethylene (POM) nanotextile that reflects 95% of sunlight and emits 75.7% in the MIR range, while resisting UV and abrasion.
- Terrestrial Extreme Environments
In deserts or tropical regions, cooling systems must operate under high temperature and humidity.- Solution: Dual-selective emitters that utilize secondary atmospheric windows (3–5 μm and 16–25 μm), combined with evaporative cooling and phase change materials (PCMs) for enhanced heat dissipation.
- Aeronautical Environments
Infrared stealth is critical. Materials must emit in non-atmospheric windows (5–8 μm) while suppressing emission in the 8–13 μm range to avoid detection.- Example: Multilayer metamaterials and photonic crystals that achieve infrared camouflage and radiative cooling simultaneously.
- Space Environments
In the vacuum of space, materials must withstand UV radiation, cosmic rays, and atomic oxygen erosion, while emitting across the full MIR spectrum.- Breakthrough: All-inorganic coatings like phosphate geopolymer paints and silica aerogels that maintain optical performance even after proton irradiation or exposure to 1200°C.
Applications and Future Outlook
These materials are not just lab-scale curiosities—they are being integrated into building coatings, personal cooling textiles, aircraft skins, and spacecraft thermal shields. The review also outlines future directions, including:
- Multi-functional materials that combine UV resistance, flame retardancy, antimicrobial properties, and self-cleaning.
- Dynamic spectral tuning for adaptive cooling/heating based on environmental conditions.
- Hybrid cooling systems that integrate radiative, evaporative, and latent heat mechanisms for maximum efficiency.
Conclusion
This comprehensive review provides a strategic framework for designing next-generation radiative cooling materials that can thrive in the most extreme environments. By combining materials science, photonics, and thermal engineering, the authors lay the groundwork for energy-efficient, passive cooling technologies that could revolutionize everything from urban infrastructure to space exploration.
Stay tuned for more cutting-edge research from Prof. Han Zhou and Prof. Di Zhang at Shanghai Jiao Tong University!
Journal
Nano-Micro Letters
Method of Research
Experimental study
Article Title
Radiative Cooling Materials for Extreme Environmental Applications
