Fire-Resistant Microtubular Fibrous Sponges by Spontaneous Hollowing and Dynamic Hybridization for Broadband Acoustic Absorption

Abstract

Conventional polymeric fibrous sponges, as universal passive acoustic control materials, provide a sustainable approach to noise mitigation. However, addressing the narrow effective acoustic bandwidth and inherent flammability remains challenging. Here, a fire-resistant hybrid fibrous sponge (HYFS) featuring broadband acoustic absorption is fabricated by the strategy of spontaneous hollowing and sacrificial template-assisted dynamic hybridization. The hierarchical phase separation within a solution jet enables the concurrent hollowing and three-dimensional self-assembly of ultrafine fibers in one step. Subsequently, a continuous inorganic sheath induced by template sacrifice was generated on the hollow fibers, forming a dynamically evolved multi-scale structural regulatory system, ranging from the microtubular fibers with hollow channels and nanoscale surface roughness to macroscopic fibrous assemblies with open inter-fiber porosity. Thus, the prepared HYFS demonstrates a remarkable noise-reduction coefficient of 0.62 at 270 g/m², along with the broadband sound absorption of effective bandwidth up to 5.5 kHz (sound absorption coefficient > 0.90). Moreover, it demonstrates outstanding fire retardancy with a peak heat release rate of 7 kW/m², representing a 75% reduction compared to the prepared polyimide sponges. This work sheds light on a novel avenue to the scalable fabrication of ultralight, fire-safe, and highly efficient broadband acoustic absorbers for practical applications.

Graphical Abstract

Keywords

Microtubular fibrous sponge / Spontaneous hollowing / Coaxial electrospinning / Fire retardancy / Acoustic absorption

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Funding

National Natural Science Foundation of China(52403004)

Science and Technology Commission of Shanghai Municipality(24xtcx00300)

Natural Science Foundation of Shanghai Municipality(24ZR1402500)

Postdoctoral Research Foundation of China(GBZ20240138)

RIGHTS & PERMISSIONS

Donghua University, Shanghai, China