Multifunctional FeCo@SiO₂/PPy-Ag/PDMS composite films with efficient electromagnetic wave absorption, favorable hydrophobicity and UV protection properties

Electromagnetic wave (EMW) absorbers are always needed to be qualified with environmental adaptability and long-term stability when applied in harsh environments with strong ultraviolet (UV) radiation, high humidity, or in high-altitude environments with variable climates. Typically, hydrophobicity and UV protection are needed for some special equipment. Herein, a flexible EMW absorbing film composed of polydimethylsiloxane (PDMS), FeCo@SiO₂ nanoparticles and polypyrrole (PPy)-Ag composite with hydrophobicity and ultraviolet protection properties is designed and prepared. Benefiting from the magneto-dielectric synergistic effect and multi-layered heterogeneous interfaces, the synthesized FeCo@SiO₂/PPy-Ag/PDMS (FSPA/PDMS) composite film exhibits excellent EMW absorption capabilities. The minimum reflection loss (RL_min) of −29.8 dB and the maximum effective absorption bandwidth (EAB) of 5.8 GHz with a thin matching thickness (1.77 mm) can be obtained. Furthermore, the FSPA/PDMS composite film demonstrates favorable hydrophobicity with a water contact angle of 128.6° and exceptional UV protection performance with an ultraviolet protection factor (UPF) value as high as 143.46. Moreover, the 180 mm × 180 mm carbonyl iron powder (CIP)@SiO₂/PPy-Ag/PDMS composite film is fabricated and measured using the arch method, both before and after an accelerated UV aging experiment, demonstrating excellent EMW absorption capabilities and remarkable UV aging resistance. This work provides a new strategy for achieving efficient EMW absorption with a thin matching thickness, alongside favorable hydrophobicity, excellent UV shielding and UV aging resistance. We believe this work holds great potential for practical applications such as aircraft, camouflage tents and protective clothing in harsh environments.