Bioinspired Layered-Gradient Nanocomposites for Intelligent Electromagnetic Skins with GHz-THz Wave Absorption,...

The development of intelligent electromagnetic skins demands scalable films integrating gigahertz (GHz)-terahertz (THz) wave absorption, electromagnetic interference (EMI) shielding, and programmable actuation. Here, we report a bioinspired bamboo-like layered-gradient system fabricated via scalable vacuum filtration, in which two types of films are constructed with distinct functionalities: a low-poly(3,4-ethylenedioxythiophene) (PEDOT) content film for microwave absorption and a high PEDOT content film for conductive network-enabled EMI shielding.The films precisely assemble Al-Fe₃O₄ nanosheets, aramid nanofibers, and PEDOT into an asymmetric architecture. A monotonic through-thickness gradient in composition creates a tailored impedance profile and strong anisotropy while minimizing conductive filler content. This design achieves effective microwave absorption at low PEDOT loading (minimum reflection loss: - 56.6 dB at 2.2 mm in the X-band). With increased PEDOT content, a percolative network is constructed, enabling Joule heating (233 °C at 20 V) and efficient EMI shielding (42.0 dB in the GHz band and 57.8 dB in the THz band). Beyond electromagnetic performance, the gradient architecture enables programmable, ethanol-triggered anisotropic actuation via differential swelling. The films also exhibit excellent thermal stability, mechanical robustness, and flexibility, ensuring reliability in harsh environments. Collectively, this gradient architecture provides a scalable platform for intelligent electromagnetic skins integrate magnetic-dielectric coupling, conductive network tuning, and stimuli-responsive actuation.