Dynamically Tunable Subambient Daytime Radiative Cooling Metafabric with Janus Wettability

Abstract Incorporating zero‐energy‐input cooling technology into personal thermal management (PTM) systems is a promising solution for preventing heat‐related illnesses while reducing energy consumption. Although concepts for passive radiative cooling materials are proposed, achieving subambient cooling performance while providing good wearing comfort remains a challenge. Here, a moisture‐wicking nonwoven metafabric is reported that assembles radiative cooling and evaporative heat dissipation to achieve high‐performance thermal and moisture comfort management. This metafabric demonstrates excellent spectral‐selectivity (sunlight reflection of ≈92%, atmospheric window thermal emissivity of ≈97%) and Janus wettability through large‐scale electrospinning and hierarchical design, and also inherits superior elasticity, air/moisture permeability of nonwoven fabric. Subambient temperature drops of ≈6.5 °C (≈750 W m −2 solar intensity) for stand‐alone metafabric are observed. Thanks to the moisture‐wicking effect (water evaporation rate of 0.31 g h −1 and water transport index of 1220%) of metafabric that enables fast evaporation of sweat, a maximum generation of 1 mL h −1 of sweat can cool the skin, thus reducing the excessive sweating risk after intense exercise. Additionally, the cooling performance of metafabric can be regulated by applying various strains (0–100%). The cost‐efficiency and good wearability of metafabric provide an innovative way to sustainable energy, smart textiles, and thermal wet comfort applications.