Lightweight but ultrahigh-strength functionally integrated absorbers: Highly effective electromagnetic wave absorption and infrared stealth

Developing a simple and efficient multi-functionally integrated absorber is promising but challenging. In this work, a lightweight but ultrahigh-strength polyvinyl alcohol (PVA)/aramid nanofiber (ANF)/carbon nanotube (CNT) (PAC) composite foam was fabricated through the self-assembly of hydrogen bonds. This composite foam had a hollow skeleton structure, achieving an ultra-high compressive strength of 6.71 MPa and could withstand a weight of more than 27,000 times its own weight. Its internal gradient pore structure provided a large number of reflection and scattering channels for the wastage of electromagnetic waves. Under the cooperation of impedance matching and multiple loss mechanisms, it exhibited a minimum reflection loss (RLmin) value of -59.12 dB and a wide effective absorption bandwidth (EAB) of 7.3 GHz. In addition, the PAC composite foam presented excellent radar and infrared stealth properties, and the radar cross-section scattering attenuation reached 42.92 dBm2, which showed great application advantages in complex environments. Therefore, such a convenient and efficient strategy is expected to provide a new route to design high-performance multifunctional integrated composite materials.