As the effects of global warming become more pronounced, many individuals are facing the challenges posed by extreme heat. For those whose work involves high temperatures, whether indoors or outdoors, staying thermally comfortable is essential. A team has created pioneering soft robotic clothing that provides thermal insulation and breathability while automatically adjusting to varying ambient temperatures, ensuring the safety of workers in hot conditions.
As the effects of global warming become more pronounced, many individuals are facing the challenges posed by extreme heat. For those whose work involves high temperatures, whether indoors or outdoors, staying thermally comfortable is essential. A team led by Dr. Dahua SHOU, Limin Endowed Young Scholar in Advanced Textiles Technologies, and Associate Professor at the School of Fashion and Textiles at The Hong Kong Polytechnic University (PolyU), has pioneered innovative thermally-insulated and breathable soft robotic clothing. This clothing automatically adjusts to changing ambient temperatures, significantly enhancing worker safety in high-heat settings. The team’s research findings have been published in the interdisciplinary journal Advanced Science.
Keeping a stable body temperature is crucial for health and productivity. High-temperature environments increase energy consumption, leading to heat stress, which can worsen chronic health conditions like cardiovascular diseases, diabetes, mental health disorders, and asthma. It can also heighten the risk of infectious disease spread. According to the World Health Organization, there were about 489,000 heat-related fatalities globally from 2000 to 2019, with 45% occurring in Asia and 36% in Europe.
Thermal protective clothing is vital for safeguarding individuals in extremely hot environments, such as firefighters on the scene and outdoor construction workers. However, traditional protective gear often suffers from fixed thermal resistance, potentially causing overheating in less extreme conditions while failing to provide adequate protection during severe heat events. To resolve these concerns, Dr. Shou and his team have developed a smart soft robotic clothing system that automatically adapts its thermal insulation for better protection and comfort across varying temperatures.
The inspiration for their research came from nature, notably the thermal regulation methods used by pigeons. Pigeons trap air with their feathers, which helps minimize heat loss. In colder temperatures, they fluff up their feathers to create a thicker layer of trapped air, enhancing warmth retention.
The innovative clothing created by the team incorporates soft robotic textiles that manage temperature dynamically. Soft actuators resembling a human exoskeleton and containing a non-toxic, low-boiling-point fluid have been strategically placed within the garment. This thermo-stimulated system transforms the fluid from liquid to gas as the ambient temperature rises, causing the soft actuators to expand. This process increases the thickness of the textile, creating more air pockets that effectively double the thermal resistance from 0.23 to 0.48 Km²/W. This clothing can maintain inner surface temperatures at least 10°C lower than standard heat-resistant gear, even when the outer surface reaches 120°C.
The special soft robotic fabric is made from thermoplastic polyurethane, making it soft, strong, and long-lasting. Importantly, it is more comfortable against the skin compared to traditional temperature-responsive clothing that uses shape-memory alloys and is versatile enough for various protective clothing applications. The soft actuators have proven resilient, showing no leakage after extensive washing tests. The material’s knitted structure minimizes convective heat transfer while allowing for good moisture breathability. This lightweight, soft robotic attire doesn’t rely on energy-consuming thermoelectric chips or circulatory cooling systems, enabling it to self-regulate temperature effectively without energy input.
Dr. Shou stated, “Wearing bulky firefighting gear can often feel extremely restrictive. Firefighters often sweat nearly a pound in their boots after exiting a fire scene. This motivated me to create a new suit that can adapt to different environmental temperatures while offering excellent breathability. Our soft robotic clothing can adjust to various seasons and climates, accommodating different work and living situations, and transitioning smoothly between indoor and outdoor conditions to maintain constant thermal comfort in intense heat.”
Dr. Shou envisions this innovation having vast applications across activewear, winter jackets, healthcare uniforms, outdoor gear, and sustainable textile insulation for buildings, which supports energy-saving objectives. With backing from the Innovation and Technology Commission and the Hong Kong Research Institute of Textiles and Apparel, Dr. Shou and his team have also explored thermo-adaptive technology for inflatable, breathable jackets and warm clothing. This soft robotic clothing is particularly beneficial in cold environments or sudden temperature drops—helping individuals stuck in wilderness situations regulate their body temperature effectively.
