S.V. Boriskina, Y. Huang, H. Zandavi, S. Hong, M. Lozano, M. Morciano, I. Uluturk, R.M. Osgood III, G. Chen
Massachusetts Institute of Technology,
Keywords: wearables, fabrics and textiles, passive thermoregulation, sustainability
Summary:Humans worked on improving wearable technologies since the dawn of the civilization. Yet, warm clothes are still typically bulky and reduce mobility, while cooling is hard to achieve without the use of active devices with embedded wiring and batteries. Sweat-wicking fabrics enhance cooling via convection, but are mostly suitable for athletic apparel as this cooling mechanism only gets activated after perspiration occurs. In contrast to other commercial technologies, wearable fabrics with engineered broadband photonic response developed at MIT provide local thermoregulation with zero carbon footprint via passive control of thermal radiation from the skin (ASC Photonics, 2(6) 769, 2015; US patent No. 9951446). This control makes possible both cooling without breaking a sweat and heating without adding uncomfortable metal layers to the wearables. Human body is an almost perfect emitter of thermal radiation, but conventional fabrics strongly absorb body heat. Polyethylene, however, exhibits a unique property of low infrared absorptance. By controlling the thickness of individual fibers, passively-cooling polyethylene fabrics can be optically engineered to either allow the body heat to escape via radiation or to be reflected back to the skin. In both cases, the fabrics remain visibly opaque, and can even efficiently reflect solar radiation. Owing to the micro-scale fiber structure, polyethylene fabrics provide high level of comfort, light weight, breathability, and excellent sweat wicking functionalities. The fabrics can be manufactured via standard industrial processes, and can find use in everyday clothes, headwear, and athletic apparel as well as in tents, vehicle covers, bandages, gloves and face masks. Last but not least, the use of polyethylene offers opportunities for easy recycling of fabrics through well-established industrial processes as well as their fabrication from recycled materials.