Tri-Mode Multicolor Composite Fibers for All-Season Self-Adaptive Thermoregulation

Addressing the substantial energy consumption from building heating and cooling is critical for climate change mitigation. Passive daytime radiative cooling (PDRC) offers a highly promising zero-energy strategy to mitigate global warming; however, it encounters several key limitations, including susceptibility to overcooling, constrained environmental adaptability, and challenges in manufacturability. Herein, we develop a trimode multicolor thermochromic canopy with distinct microsphere-rich and pore-rich zones in orthogonal polytetrafluoroethylene (PTFE) fibrous membranes. This design achieves programmable multitemperature spectral responses, including high mid-infrared emissivity (0.94) in the atmospheric transparency window, competitive near-infrared reflectance (93.7%), and visible light modulation capability of 30.44% via polychromic thermochromic microcapsules (TMs). Promisingly, our PTFE/TM composite enables three autonomous operational modes, yielding a maximum subambient daytime cooling of 7.6 °C in hot conditions, heating of 5.4 °C in cold conditions, and a stable intermediate state at comfortable temperatures. The composite also exhibited excellent durability and superhydrophobicity. EnergyPlus simulations confirm the significant global potential, showing substantial annual energy savings and CO 2 emission reductions across diverse climates, outperforming static cooling materials by effectively avoiding overcooling penalties. This work provides a viable zero-energy pathway for mitigating urban heat island effects and promoting climate-resilient building thermal regulation.