Owl-Inspired Coupled Structure Nanofiber-Based Aerogels for Broadband Noise Reduction

Noise pollution, as one of the three major pollutants, has brought serious harm to human life. Existing single-structured acoustic materials inevitably compromise between good low and high-frequency acoustic performance. Herein, mimicking the efficient noise absorption structure of owl's skin and feathers, owl-inspired coupling structure nanofiber-based aerogels (OSNAs) were created by integrating the emulsion-templated freeze-reconstruction method. The owl feather layer of the aerogel can effectively absorb high-frequency noise, while the cavity layer can dissipate low-frequency noise through the resonance effect, thus realizing the effective absorption of broadband noise. The noise reduction coefficient (NRC) of OSNAs reaches 0.58 and up to 0.69 with an additional 1 cm back air layer. Moreover, the OSNAs can reduce the noise of the car engine by 8.9 dB. In addition, the OSNAs showed good mechanical stability and maintained their intact structure after 100 compressions. This study paves the way for advanced noise control materials that can significantly alleviate noise pollution.