Wang Yufeng, Liu Song, Zhang Xiaobo, Liu Ying, Zhu Tianyi, Ji Baiyu, Chen Jianglong, Cheng Yuanbo, Fan Wei, Miao Yue-E, Willenbacher Norbert, Zhang Chao, Liu Tianxi
State Key Laboratory of Advanced Fiber Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
Department of Mechanical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong 999077, China.
ACS Nano. 2025 May 27;19(20):19328-19339. doi: 10.1021/acsnano.5c02609. Epub 2025 May 13.
Micronanoporous structures hold high potential as radiative sky-cooling materials for zero-energy thermal regulation in enclosed spaces subjected to high temperatures and direct sunlight, owing to their combination of thermal insulation and sunlight scattering features. However, their constrained ability to reflect sunlight across the entire solar spectrum, coupled with the inefficient dissipation of excess internal heat, restricts their applicability in diverse cooling scenarios. Herein, we present a gradient cross-linked polymerization strategy for preparing a gradient porous nanocomposite film. This film features a dual-gradient distribution of nanoparticle content and pore size, achieving a solar reflectance of 96.2% and demonstrating thermal rectification properties with a thermal rectification factor of 30%. Functioning effectively as a thermally rectified radiative cooling panel, this gradient film delivers energy-efficient and adaptive cooling for multiple enclosed environments, regardless of whether indoor temperatures exceed or fall below ambient outdoor temperatures. This gradient film achieves an extra cooling effect of 2.4 and 2.2 °C for unheated and self-heated enclosed environments, respectively, compared to the cooling effect using conventional porous nanocomposite films. The gradient structural design for porous structural radiative cooling materials demonstrates multiscenario adaptive radiative cooling applications.
微米纳米多孔结构作为辐射天空冷却材料具有巨大潜力，可用于高温和直射阳光环境下封闭空间的零能耗热调节，这得益于其隔热和阳光散射特性的结合。然而，它们在整个太阳光谱范围内反射阳光的能力有限，再加上多余内部热量的低效耗散，限制了它们在各种冷却场景中的适用性。在此，我们提出一种梯度交联聚合策略来制备梯度多孔纳米复合薄膜。该薄膜具有纳米颗粒含量和孔径的双梯度分布，实现了96.2%的太阳反射率，并展示出热整流特性，热整流因子为30%。这种梯度薄膜作为热整流辐射冷却板能有效发挥作用，为多个封闭环境提供节能且自适应的冷却，无论室内温度高于还是低于室外环境温度。与使用传统多孔纳米复合薄膜的冷却效果相比，这种梯度薄膜在未加热和自热的封闭环境中分别实现了2.4和2.2℃的额外冷却效果。多孔结构辐射冷却材料的梯度结构设计展示了多场景自适应辐射冷却应用。
