CTAB-Engineered Electro-Blown PVDF Nanofibrous Air Filters with Enhanced Charge Retention, Filtration Efficiency, and Antibacterial Functionality

Air pollution, particularly particles smaller than 0.3 µm (PM₀.₃), necessitates the development of nanofiber-based electret filters with high efficiency, low pressure drop, and long-term charge stability. In this study, PVDF nanofibrous filters incorporating cetyltrimethylammonium bromide (CTAB) were fabricated via electroblowing (EB), and the effects of CTAB content (0–1 wt.%) on fiber morphology, electrostatic chargeability, filtration performance, and antibacterial properties were investigated. EB was also compared with solution blowing (SB) to evaluate the role of the electric field during fiber formation. FTIR analysis confirmed β-phase dominance, with increasing CTAB content enhancing molecular alignment. SEM results showed reduced fiber diameter, reaching 122 ± 37 nm at 1 wt.% CTAB, although excessive addition impaired jet stability. After corona discharge, filtration efficiency (η) and quality factor (QF) improved for all samples, with PVDF1 achieving 99.96% efficiency and ∼45% increase in QF. Enhanced charge stability was maintained for up to one month due to increased charge trapping. CTAB also improved hydrophilicity and imparted antibacterial activity, while reducing tensile strength due to jet instability. Overall, CTAB-assisted electroblowing enables the fabrication of PVDF nanofibrous filters with enhanced electret performance and multifunctional properties, offering strong potential for high-performance and sustainable air filtration applications.