Direct synthesis of lightweight fiber sponges with interconnected nanopores structured fibers for absorbing low-frequency noise

Noise pollution from transportation industries poses many challenges to people's health and the global economy. Most noise-absorbing materials suffer from the difficulty of achieving good noise absorption while maintaining light weight. In this study, we propose a feasible strategy to assemble porous fiber sponges (PPFS) based on electrospinning method. Modulating the phase separation rate of charged jet allows for the direct assembly of fiber sponges consisting of interconnected nanopores (30-70 nm) structured fibers. The resultant PPFS possess lightweight feature (volume density of 9.06 mg cm-3) and good mechanical properties (full recovery from 60% deformation). The sponges also show excellent low-frequency sound-absorbing performance (the sound absorption coefficient at 500 Hz is 0.78). Meanwhile, the noise reduction coefficient (NRC) of the fiber sponges reaches 0.57 when thickness is 30 mm, which could absorb white noise and high decibel noise efficiently. This work offers a fresh solution to develop lightweight and efficient sound-absorbing materials.