High-efficiency absorption and acoustoelectric conversion in heterogeneous nanofibers: a two-pronged approach to full-frequency de-noising

Abstract

The generation of full-frequency noise from variable-speed motors and engines constitutes a significant threat to human health and contributes to global energy loss. To address this pressing issue, a bilayer nanofibrous membrane was designed and fabricated with improved acoustoelectric conversion properties and full-frequency noise absorption capabilities. The hydroxyl (–OH) in cellulose nanocrystals (CNC) and the cyano (–CN) in polyacrylonitrile (PAN) interacted to dramatically increase the proportion of PAN's zigzag conformation to 89.9% via the combined effect of an electrostatic field and molecular induction, resulting in improved acoustoelectric conversion efficiency. The nanofiber device demonstrates exceptional performance, reducing low-frequency noise from 110 dB to 96 dB and generating peak electrical outputs of 10.92 V and 12.9 μA. Furthermore, heterogeneous and juxtaposed nanofibers of polystyrene (PS) and polyamide 66 (PA66) were electrospun parallelly to address the challenge of reducing medium and high-frequency noise, leveraging their vastly different elastic modulus properties. The stacked structure of the two layers further amplifies the synergistic effect on the noise absorption medium and high-frequency noise n and acoustoelectric conversion, leading to enhanced full-frequency noise suppression, thereby reducing sound pressure to 68 dB with a sound absorption efficiency of 0.7. This novel fibrous film presents a highly promising approach for mitigating the effects of full-frequency noise pollution, serving as a potential energy source.