Multifunctional ANF/ CNT/FCIP aerogels with superior sound and electromagnetic wave absorption and mechanical properties

Aerogels exhibit bright prospect for multifunctional applications in noise reduction, radar stealth, load bearing, etc. Existing aerogels however suffer from poor sound absorption at low frequencies, narrow-band electromagnetic wave absorption and low structural strength. Here, we propose a novel lightweight aerogel composed of aromatic polyamide nanofiber (ANF)/ carbon nanotubes (CNT)/ flake carbonyl iron powder (FCIP) to boost acoustic/electromagnetic absorption and mechanical performance simultaneously. The FCIP additives create surface roughness and enlarge the pore size of the aerogel. As a result of the enhanced viscous energy dissipation by surface roughness and better impedance match achieved due to the enlarged pores, sound absorption at low frequency is significantly improved. Besides, the electrically and magnetically conductive network generated by embedded FCIP brings about effective electromagnetic absorption covering the whole X-band. Moreover, the aerogels undergo an increase in skeleton thickness and pore size by FCIP, resulting in maximum compressive stress increment. Our study provides clear guidance for the performance enhancement of aerogels that advances the development of aerogels for multifunctional applications.