Printable Phase-Change Radiative Cooling Polymer for All-Day Building Thermal Management

Abstract

Passive daytime radiative cooling (PDRC) offers a green and sustainable solution for regulating building thermal comfort. However, existing PDRC material systems still face challenges, such as the risk of nighttime overcooling and complex fabrication processes, while achieving efficient daytime cooling. To address these issues, we developed a multifunctional cooler by synergistically integrating thiol–ene/acrylate click chemistry with digital light processing (DLP) 3D printing. Under UV irradiation, thiol–ene/acrylate click chemistry induced phase separation and the formation of a cross-linked porous polymer network. By further incorporating phase-change microcapsules and hydrophobic modification, a polymer cooler integrating thermal regulation and radiative cooling was developed. The obtained TPHP15-C/T5 exhibited excellent spectral properties, with an average solar reflectance of 94.15% and an average atmospheric window emissivity of 98.17%. Under an average solar irradiance of 499.35 W·m–2, TPHP15-C/T5 achieved a maximum subambient cooling of 4.63 °C and an average subambient cooling of 3.45 °C. At night, the exothermic phase transition of the phase-change microcapsules (PCMs) in TPHP15-C/T5 provided thermal buffering, with an average temperature difference of 0.76 °C, thereby mitigating nighttime overcooling. Meanwhile, the sample also exhibited a compressive stress of 2.73 MPa at 8.26% strain, a water contact angle of 152.2°, and stable spectral performance under humid conditions. Thermal conductivity, hot plate, and cold plate tests further confirmed its thermal insulation and heat preservation capabilities. Building energy simulations revealed that when used as a roof-envelope material, it could reduce summer energy consumption by 27.34% compared to the baseline building. Overall, this study provides a feasible strategy for applying 3D-printed phase-change radiative cooling materials to building thermal management by combining manufacturability, all-day thermal regulation capability, and building energy-saving potential.