Hierarchically Designed Electrospun Passive Daytime Radiative Cooling Metafabric Enabling Moisture Transport and Fire Safety

ABSTRACT Passive daytime radiative cooling (PDRC) textiles can reduce thermal stress by reflecting sunlight and emitting heat through the atmospheric window, yet practical use is limited by insufficient solar scattering, moisture transport, and polymer fire hazards. A multifunctional electrospun metafabric was developed via hierarchical structural design and compositional optimization. Specifically, semi‐cylindrical polyvinylidene fluoride (PVDF) fibers enhanced backscattering, subwavelength roughness promoted diffuse scattering, and exposed BaSO ₄ particles maximized particle‐air refractive index discontinuity to strengthen Mie resonances. The metafabric achieved 94.0% solar reflectance and 91.2% mid‐infrared emissivity, yielding the lowest theoretical cooling power demand (23.6 W·m ⁻² ) among tested samples. Outdoor field tests demonstrated ∼7.1°C lower temperature than bare skin across seasons, and building‐scale simulations predicted 40%–58% cooling‐energy savings across major climate zones. Dynamic wetting ensured physiological comfort through rapid sweat transport and a shift from evaporative to radiative cooling, reducing perspiration burden by 77.1% vs. cotton under typical summer conditions. For fire safety, the metafabric exhibited a low total heat release (4.8 kJ·g ⁻¹ ), a high char residue (45.0%), and suppressed toxic volatile emissions. This integrated design supports PDRC textiles as a sustainable cooling strategy, simultaneously optimizing cooling, comfort, and fire safety for both occupational and emergency wear.