Scalable multifunction porous film as a thermal insulating radiative cooler and triboelectric nanogenerator to save and generate energy.

Passive radiative cooling and triboelectric generation provide a way to achieve zero-energy cooling and sustainable electricity generation, respectively. However, they are frequently studied independently and lack integration. Herein, a scalable porous film for thermal insulation, passive radiative cooling and triboelectric generation has been developed using a facile emulsion polymerization method. Abundant micrometer size air holes within the multifunction porous film (MFPF) result in a low thermal conductivity of 0.05 W/(m·K), and strong scattering occurs at the interface between the air holes and Ecoflex, resulting in high solar reflectance. Simultaneously, a high infrared emittance of 0.95 is attained owing to the molecular vibrations of Ecoflex. The MFPF delivers a theoretical net passive radiative cooling power of 29.04 W/m2 and 122.68 W/m2 during the daytime and nighttime. Additionally, it achieves an actual temperature drop of approximately 4.5 °C under direct sunlight on a clear day. Moreover, a triboelectric effect of a maximal power density of 0.03 W/m2 is achieved due to the triboelectric-negative nature of Ecoflex. This film can achieve passive radiative cooling in the summer while more effectively blocking heat penetration due to the significant temperature difference between the outdoors and indoors. Meanwhile, the film can convert sustainable energy into electricity. • A scalable porous film with thermal insulation, passive radiative cooling and triboelectric generation. • The film has low thermal conductivity of 0.05 W/(m·K), which more effectively blocking heat penetration. • The film has theoretical passive radiative cooling power of 29.04 W/m2 and 122.68 W/m2 during the daytime and nighttime. • A triboelectric effect of a maximal power density of 0.03 W/m2 is achieved. [ABSTRACT FROM AUTHOR]