Hierarchical porous dual-mode thermal management fabrics achieved by regulating solar and body radiations.

ABSTRACT

Personal thermal management (PTM) of fabrics is vital for human health; the ever-changing location of the human body poses a big challenge for fabrics to maintain a favorable metabolic temperature. Herein, a dual-mode thermal management fabric is designed to achieve both cooling and heating functions by regulating simultaneously solar and body radiations. The cooling or heating mode can be exchanged by flipping the fabric without an external energy supply. The passive cooling side consists of an electrospun polyacrylonitrile (PAN) fabric with a hierarchical porous structure, exhibiting high sunlight reflectance (91.42%) and an ∼14 °C temperature decrease under direct sunlight irradiation. The co-existence of nanoscale and microscale pores is proven to be essential for improved cooling performances. The other heating side, coated with an MXene layer, shows high photothermal conversion efficiency (37.5%) and outstanding heating capability outdoors. Furthermore, the contrary mid-infrared emissivity of the two sides (high emissivity of the cooling side while low emissivity of the heating side) leads to the dual-mode passive regulation of body thermal energy. Besides, this fabric demonstrates satisfactory wearability and excellent stability. Our work proposes an energy-saving and cost-effective approach for PTM fabrics potentially suitable for various scenarios (e.g., indoors/outdoors, summer/winter, low/high latitude areas).