Acoustic “re-charging” of nanofiber air filters

filtration efficiency to ∼75% (solid) and ∼74% (oil), with a pressure drop of 96 Pa. Subsequent acoustic stimulation (100 Hz, 110 dB, 10 min) restored the efficiency to 99.99% for solid and 92.90% for oily particles, while lowering the pressure drop to 45 Pa, performance that matches that of the pristine, as-spun membranes. This recovery stems from sound-induced fiber vibration, which activates a synergistic piezoelectric-triboelectric mechanism within the microphase-separated composite, replenishing surface charge and expanding the pore structure. The process is repeatable over 30 cycles without decay and also enhances back-pulse cleaning. By introducing acoustic energy as a distinct, non-contact regeneration regime, this work provides a scalable pathway toward energy-efficient, durable, and high-performance air filtration systems.