Dielectrophoretic Assembly of BaTiO₃ Radiative Cooling Textiles for Proactive Urban Cooling

The urban heat island (UHI) effect threatens sustainable urban development. Passive daytime radiative cooling textiles are promising but face a trade-off between optical performance and mechanical-chemical stability. Here, we report the first use of dielectrophoretic assembly to create a BaTiO₃ surface-mineralized fibrous textile with simultaneous high solar reflectance and mechanical flexibility for radiative cooling, and by developing a novel dielectrophoretic assembly method to fabricate a highly flexible, high-BaTiO₃-loading fibrous textile. During electrospinning, electric field gradients induce targeted migration and self-assembly of BaTiO₃ nanoparticles (NPs) onto fiber surfaces, creating a semi-exposed architecture that maximizes backward Mie scattering while retaining a flexible polymer core (PVDF-b-PTFE matrix). The resulting textile achieves 96.78% solar reflectance (99.49% in the visible region) and 96.19% atmospheric window emissivity, with a breaking strain of 170%. It delivers a net cooling power of 110.1 W·m^-2, reducing surface temperatures by ca. 20°C compared to conventional building walls. Multiscale experiments and Weather Research and Forecasting (WRF) simulations indicate that large-scale deployment of this conformal cooling textile can modify and, under the modeled conditions, reverse the classical UHI circulation.