ABSTRACT
Heating requirements for residential and commercial dwellings result in significant energy consumption and deleterious environmental effects. Personal radiative thermal management textiles regulate the wearer's body temperature by controlling the material's intrinsic optical properties. Passive heating textiles suppress radiative heat losses and therefore significantly reduce the energy consumption required for building heating systems. Guided by an optical theoretical approach, a transparent radiation shield (TRS) is designed based on silver nanowires (AgNWs) that can suppress human body heat with simultaneous visible light transmittance anticipated for practical fabrics. We experimentally demonstrated a TRS with large infrared light reflectance (low emissivity of 35%) and a visible (VIS) transparency value of 75% (400-800 nm). The results are well corroborated by the Mie scattering theory and the wire-mesh equivalent sheet impedance model, which provide fundamental mechanism understanding and guidance toward higher performance. The TRS is fabricated by a simple, solution-processing method with thermoplastic elastomer protective layers, granting notable stretching capabilities, mechanical robustness, and conformability to any body shape or object. The rigorous theoretical strategy enables the scalable synthesis of low-emissivity and visibly transparent textiles for personal thermal comfort.
ABSTRACT
Multifunctional and long-term stable wearable heating systems have attracted extensive attention from experts, yet smart textiles that only rely on harvesting the body's heat without additional energy still face huge challenges in practical applications. Herein, we rationally prepared the monolayer MXene Ti3C2Tx nanosheets via an in situ hydrofluoric acid generation method, which was further employed to construct a wearable heating system of MXene @ polyester polyurethane blend fabrics (MP textile) for the passive personal thermal management through a simple spraying process. Owing to the unique two-dimensional (2D) structure, the MP textile presents the desired mid-infrared emissivity, which could efficiently suppress the thermal radiation loss from the human body. Notably, the MP textile with an MXene concentration of 28 mg/mL exhibits a low mid-infrared emissivity of 19.53% at 7-14 µm. Significantly, these prepared MP textiles demonstrate an enhanced temperature of more than 6.83 °C compared with those of favorably traditional fabrics, involving the black polyester fabric, pristine polyester polyurethane blend fabric (PU/PET), and cotton, suggesting a charming indoor passive radiative heating performance. The temperature of real human skin covered by MP textile is 2.68 °C higher than that covered by cotton fabric. Impressively, these prepared MP textiles simultaneously possess attractive breathability, moisture permeability, mechanical strength, and washability, which provide new insight into human body temperature regulation and physical health.