Porous Gradient Composite with Dependable Superhydrophobic Protection for Multifunctional Electromagnetic Interference Shielding

Simultaneously realizing high electromagnetic interference (EMI) shielding and superhydrophobic properties of materials to ensure long-term stability in harsh environments is a very challenging task. In this work, an efficient superhydrophobic EMI shielding composite with a gradient conductivity and porous structure was prepared by chemical plating, in situ polymerization, and spraying processes. Benefiting from the structural characteristics of porous multilayers and the rational distribution of electromagnetic two-component fillers in the composite, as well as the synergistic effect of various electromagnetic loss mechanisms, a perfect unification of high EMI shielding effectiveness of 62 dB and high absorption coefficient (A) of 0.77 was achieved. Meanwhile, a thin layer with further enhanced impedance matching was constructed on the surface of the composite using double-sized mixed particles of Fe₃O₄ and graphite particles (GP) in conjunction with the spraying process. The rough surface microstructure of the thin layer bestows the composite superhydrophobicity, and even after long-term immersion in acidic and alkali solutions or repetitive bending, the water contact angle still remains at a high level. Additionally, the sprayed materials also endow the composite with outstanding photothermal conversion properties that enhance the ability to adapt to environmental changes, significantly raising the practical application value.