Blown-Spun PVDF-HFP/SiO 2 Composite Nanofibers for Efficient Daytime Radiative Cooling

In response to the dual global challenges of energy consumption and environmental sustainability, where building cooling accounts for 15%–20% of global energy usage, passive radiative cooling (PRC) has emerged as a promising solution. PRC enables energy-free temperature reduction by leveraging materials with specific optical characteristics. In this study, porous poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)/SiO 2 composite nanofiber membranes incorporating nanoscale SiO 2 particles were fabricated via solution blow spinning (SBS). The resulting membranes feature uniform fibers formed by high-speed airflow shearing and an interconnected nano-micro hierarchical porous network. These structures synergistically combine the Mie scattering of 300 nm SiO 2 nanoparticles with the intrinsic infrared emissivity of C–F bonds in PVDF-HFP. The composite fiber membrane with 12% SiO 2 exhibits a high solar reflectance of 94.9% across the solar spectrum (λ = 0.3–2.5 μm) and a high emissivity of 97.4% within the atmospheric window (λ = 8–13 μm), resulting in an average daytime cooling of 7.8 °C. Outdoor tests on building and vehicle models showed average daytime cooling values of 6.0 and 4.5 °C, respectively. The structural tunability of the SBS technique provides a promising route toward radiative cooling materials.