Flexible ceramic nanofibrous sponges with hierarchically entangled graphene networks enable noise absorption

Abstract

Traffic noise pollution has posed a huge burden to the global economy, ecological environment and human health. However, most present traffic noise reduction materials suffer from a narrow absorbing band, large weight and poor temperature resistance. Here, we demonstrate a facile strategy to create flexible ceramic nanofibrous sponges (FCNSs) with hierarchically entangled graphene networks, which integrate unique hierarchical structures of opened cells, closed-cell walls and entangled networks. Under the precondition of independent of chemical crosslinking, high enhancement in buckling and compression performances of FCNSs is achieved by forming hierarchically entangled structures in all three-dimensional space. Moreover, the FCNSs show enhanced broadband noise absorption performance (noise reduction coefficient of 0.56 in 63–6300 Hz) and lightweight feature (9.3 mg cm–3), together with robust temperature-invariant stability from –100 to 500 °C. This strategy paves the way for the design of advanced fibrous materials for highly efficient noise absorption.

Hypocrystalline ceramic aerogels for thermal insulation at extreme conditions

“…We next experimentally evaluated the stretchability of ZAGs with uniaxial quasi-static tension, revealing that the ZAGs can withstand a nearly linear tensile strain up to 18.5% followed by a nonlinear tensile strain up to 40% (Fig. 3h , Supplementary Video 3 ), which is comparable to the highest values reported so far 13 , 21 , 22 , 41 , 42 (Supplementary Fig. 26 ).…”

“…The recoverable strain is notably higher than previously reported values for ceramic nanofibrous aerogels, which tops out at 80% (refs. 13,14,31,[39][40][41][42][43] ). The ZAGs could be repeatedly compressed at 50% strain for 1,000 cycles with little stress degradation, less than 7%.…”

Ultralight Single‐Walled Carbon Nanotube Aerogels for Low‐Frequency Sound Absorption

“…Therefore, it is necessary to develop lightweight materials that can absorb low-frequency sounds. [6,7] Porous materials [8] and fibrous materials [9] are typical lightweight sound-absorbing materials. These materials lose acoustic energy because of the viscous friction on the pore walls and thermal loss within the pores.…”

“…[19][20][21][22][23] Furthermore, ultralight fibrous sound-absorbing materials based on microfibers fabricated by the electrospinning method have been reported to have effective low-frequency sound-absorption performance. [5,6,[24][25][26] The general design principle for enhancing the low-frequency sound-absorption performance of fibrous sound-absorbing materials is to reduce the diameter of the constituent microfibers to increase the contact area and acoustic energy loss due to the friction between fibers. [6,27] Although these studies have created complex porous structures within ultralight materials that are advantageous for sound absorption, they have only focused on the loss of air-borne sound within the material, and the low-frequency sound absorption is limited.…”

“…[5,6,[24][25][26] The general design principle for enhancing the low-frequency sound-absorption performance of fibrous sound-absorbing materials is to reduce the diameter of the constituent microfibers to increase the contact area and acoustic energy loss due to the friction between fibers. [6,27] Although these studies have created complex porous structures within ultralight materials that are advantageous for sound absorption, they have only focused on the loss of air-borne sound within the material, and the low-frequency sound absorption is limited. The low-frequency sound-absorption property of an ultralight sound-absorbing material can be further enhanced by applying a design principle that also considers the loss of solid-borne sound propagating through the material framework effectively.…”