Colored Sandwich-Structured Metafabrics for Passive Radiative Cooling

Developing passive radiative cooling (PRC) fabrics that combine high solar reflectance with desirable coloration, particularly purple, remains challenging due to the spectral trade-off between solar reflection and visible light absorption. Here, a "colored-white-colored" sandwich-structured metafabric is designed to balance aesthetic appearance and cooling performance. The fabric consists of spectrally selective purple skin layers and a highly reflective scattering core. The skin layers, composed of polyurethane (TPU) fibers and purple metal-organic framework ZIF-67, enable selective visible light absorption and enhanced mid-infrared emission, while the TPU/ZnO nanofiber core enhances broadband solar reflection through strong scattering. By spatially decoupling coloration and reflection, the fabric achieves a high solar reflectance of 90.6% and a mid-infrared emissivity of 94.6%. Outdoor tests show a maximum sub-ambient cooling of about 5.2 oC during daytime. Simulated and real-skin evaluations confirm superior personal cooling performance compared with commercial dyed cotton fabrics. The fabric also exhibits good moisture permeability and hydrophobicity, with a water vapor transmission rate of ~24.01 mg·cm-2·h-1 and a water contact angle of ~120o, which facilitates sweat evaporation and heat dissipation. This work provides a practical strategy for designing colored passive radiative cooling fabrics with aesthetic appeal, high visibility, and efficient thermal management.