“Sandwich Structured” Composite Film with Double Barrier Radiative Cooling, Adjustable Heating, and Multi-reflective Electromagnetic Interference Shielding for All-Weather Protection

Extreme weather conditions and electromagnetic waves pollution are common and pose a serious threat to equipment operation and human health. However, existing materials for temperature management and electromagnetic protection are difficult to adapt to the changing environment. Therefore, a “sandwich structured” composite film (PHAN₂P) was developed in this study. First, the Mie scattering of hollow glass microspheres (HGMs) provides high solar reflectance up to (85.5%), and second, the vibration of Si–O chains in HGMs and polydimethylsiloxane achieves high infrared emissivity (95.3%), which provides subambient radiative cooling at an average of 7.4 °C. And it can save more than 20 MJ/m² of energy in a medium-sized building over the course of a year. Surprisingly, the PHAN₂P can reach a surface temperature of 55 °C with an operating voltage of only 1 V, enabling low-pressure, low-energy Joule heating. In addition, a double conductive reflective layer provides a stable electromagnetic interference (EMI) shielding effectiveness (SE) of 26 dB. Taken together, PHAN₂P provides a new solution for thermal management and electromagnetic protection applications in buildings by enabling temperature adaptation and EMI shielding without switching surfaces.