Electrically Activated Ultrathin PVDF-TrFE Air Filter for High-Efficiency PM1.0 Filtration

Ultrafine particulate matter (PM) in indoor air has become a serious concern for public health. Therefore, there is a growing interest in filters that can be installed on the window frames of ordinary homes to improve the indoor air quality by natural passive ventilation without using expensive forced air circulation systems. Thus, these filters require a high filtering efficiency and high air permeability and visibility, which do not compromise the original functionality of the windows. The filters developed for this purpose to date have demonstrated a high filtering efficiency for PM2.5 but a relatively low efficiency for PM1.0. Here, the performance of the ultrathin poly[(vinylidenefluoride-co-trifluoroethylene) (PVDF-TrFE) nanofiber air filter capable of high-efficiency PM1.0 filtration is reported. To enhance the PM1.0 filtering efficiency, the filter is electrically activated by the polarization of dipoles and triboelectrification using the ferroelectric nature and triboelectrically negative property of the PVDF-TrFE filter layer. The electrically activated PVDF-TrFE filter demonstrates a PM1.0 filtering efficiency of over approximate to 88% after polarization, which is further improved to approximate to 94% after triboelectrification. In addition, the filter is ultrathin and air-permeable with 65% light transmittance. The methods introduced in this work can be adopted to develop high performance, highly visible, and air-permeable filter media.