A Janus Textile Capable of Radiative Subambient Cooling and Warming for Multi‐Scenario Personal Thermal Management

Abstract

Textiles with radiative cooling/warming capabilities provide a green and effective solution to personal thermal comfort in different climate scenarios. However, developing multiple‐mode textiles for wearing in changing climates with large temperature variation remains a challenge. Here a Janus textile is reported, comprising a polyethersulfone (PES)‐Al2O3 cooling layer optically coupled with a Ti3C2Tx warming layer, which can realize sub‐ambient radiative cooling, solar warming, and active Joule heating. Owing to the intrinsically high refractive index of PES and the rational design of the fiber topology, the nanocomposite PES textile features a record high solar reflectance of 0.97. Accompanied by an infrared (IR) emittance of 0.91 in the atmospheric window, sub‐ambient cooling of 0.5–2.5 °C is achieved near noontime in humid summer under ≈1000 W m−2 solar irradiation in Hong Kong. The simulated skin covered with the textile is ≈10 °C cooler than that with white cotton. The Ti3C2Tx layer provides a high solar‐thermal efficiency of ≈80% and a Joule heating flux of 66 W m−2 at 2 V and 15 °C due to its excellent spectral selectivity and electrical conductivity. The switchable multiple working modes enable effective and adaptive personal thermal management in changing environments.

Dual‐mode smart flipping materials and devices for thermal management

“…[77] In their study, Yue et al [46] created wearable Janus MnO 2 hybrid films with distinctive radiative characteristics for every side. Li et al [78] fabricated a Janus textile that possessed three operational modes, including solar heating, radiative cooling, and electric warming. The textile was fabricated in two steps, resulting in a straightforward Janus structure.…”

Recent advances in microfluidic fiber‐spinning chemistry

“…However, for most passive cooling textiles, the harvest of solar radiation has not been appreciated. 65,66 In the cold winter, these passive cooling textiles cannot satisfy the requirement of heat harvesting. Aimed at this issue, Chen's group 67 first achieved a thermoregulatory textile with adjustable F I G U R E 1 0 Microfluidic FSC-directed hydrogel fabrics.…”

“…To this end, nanofibrous films with passive cooling capacity have been applied as cooling textiles without energy consumption. However, for most passive cooling textiles, the harvest of solar radiation has not been appreciated 65,66 . In the cold winter, these passive cooling textiles cannot satisfy the requirement of heat harvesting.…”

Thermochromic Conductive Fibers with Modifiable Solar Absorption for Personal Thermal Management and Temperature Visualization

“…After that, other moisture/temperature-responsive actuators based on a metalized polyamide heterostructure were designed, which expands the adaptability compared with traditional static textiles. , A few works have focused on metal-coated elastomers. The crack caused by stretching determines the amount of body thermal radiation that could pass through the composites. − Another strategy is the Janus structure, where heating and cooling layers are integrated on two sides of a fabric, respectively. − The users could choose a suitable side facing the ambient according to their own needs. A comparison of adjustable spectral characteristics between different personal thermal management textiles in the literature is shown in Table S1 in detail.…”