Janus Particles Stabilized Passive Cooling Porous Composites

Passive radiative cooling is promising for meeting refrigeration needs and addressing global energy challenges. However, conventional radiative coolers with static cooling properties suffer from limited performance under thermal shock and heat accumulation. Herein, an intelligent passive radiative cooling material combining highly efficient radiative thermal dissipation and dynamic thermal buffering was fabricated via a scalable one-pot strategy. A ternary PMMA/LA/BN porous composite was fabricated via an inverse Pickering emulsion template stabilized by self-assembly of amphiphilic Janus particles at the oil–water interface, and the porous framework effectively reflects solar radiation. Moreover, BN nanosheets serve as optical scattering centers, enhancing solar reflectivity, while lauric acid (LA) serves as a phase change component, and their synergistic integration endows the composite with high radiative cooling efficiency and dynamic thermal regulation capability. The porous composite exhibits a reflectivity of 95.1% in the solar spectral band (0.3–2.5 µm) and an emissivity of 96.5% in the atmospheric window band (8–13 µm). Meanwhile, the incorporation of LA effectively suppressed drastic fluctuations and demonstrated thermal shock mitigation capability. This porous composite, with synergistic radiative cooling and phase change thermal buffering, provides a strategy for developing adaptive thermal management materials in complex real-world environments.