High-performance sub-wavelength acoustic absorption via ZIF-8@PVDF-TrFE composite nanofiber for compact low-frequency noise control

• ZIF-8 in PVDF-TrFE nanofibers boosts piezoelectricity and sound absorption. • Nanofibers generate 3.39 V under 2 N stress over 9 cm², aiding energy harvesting. • Optimized nanofiber membrane achieves 0.63 average sound absorption at 225 Hz. • A compact strategy for efficient low-frequency noise control is demonstrated. Developing sub-wavelength acoustic materials for low-frequency noise control within compact size ranges is a significant challenge and an urgent necessity to achieve exceptional acoustic performance. This study successfully integrated ZIF-8 uniformly into PVDF-TrFE nanofibers, resulting in increased surface roughness, a 139% enhancement in specific surface area, enhanced fiber strength and ductility, and a 12% increase in the β-phase content of PVDF-TrFE, which collectively contributed to an open-circuit output voltage of 3.39 V over a 3 × 3 cm area. The ZIF-8@PVDF-TrFE nanofibrous membrane demonstrated significantly enhanced sound absorption compared to traditional foam and micro-perforated panels (MPPs) within the 50-1000 Hz frequency range. It extended the lower limit frequency to 205 Hz, with a maximum average sound absorption coefficient of 0.63. Within the experimental membrane thickness range of 0.25-0.75 mm, fitting results indicated a linear relationship between membrane thickness and sound absorption enhancement in foam assemblies. In MPP assemblies, thinner membranes were more effective, especially with a 2 cm cavity depth. This outstanding performance is attributed to the porosity, enhanced damping, and combined mass-spring and piezoelectric effects of the ZIF-8@PVDF-TrFE membrane, presenting a promising strategy for low-frequency noise control in applications where weight and volume are critically constrained.