Jellyfish-Coral Bioinspired Bilayer Architecture for Integrated Infrared/EM Stealth and Underwater Acoustic/Drag Reduction.

Biological systems have long inspired the design of functional materials, yet achieving functionally decoupled integration of multiple biomimetic functionalities within a single platform, especially across different media, remains a major challenge. Here, we report a jellyfish-coral bioinspired bilayer architecture that enables infrared (IR, 2.5-25 µm) stealth and electromagnetic (EM, 2-18 GHz) shielding above water as well as acoustic stealth (1-10 kHz) and drag reduction underwater. The upper layer, inspired by jellyfish microvilli, comprises a microvillar Si nanoarray that exhibits ultra-low infrared emissivity (< 20%) and air-film-mediated drag reduction, as evidenced by a water contact angle of 108.64°. The lower layer, inspired by coral skeletons, consists of a porous SiC framework decorated with in situ grown nanowire networks, which delivers broadband electromagnetic absorption (minimum reflection loss of -56.02 dB and an effective absorption bandwidth of 10 GHz at a thickness of only 3 mm) together with efficient acoustic wave dissipation (absorption coefficient ≈ 0.7 at an incident angle of 80°). These two bioinspired layers are monolithically integrated while preserving their respective functionalities, such that each stealth modality operates independently and without detrimental coupling. Consequently, the metastructure achieves robust, multispectral stealth performance in both sea-surface and underwater environments.