Electreted polyetherimide–silica fibrous membranes for enhanced filtration of fine particles

• Single-step fabrication of electreted fibrous membranes for filtration.
• Effect of inorganic electrets on filtration performance was studied.
• Self-cleaning property was achieved by tuning the structure of membranes.
• Better filtration performance than commercial PP filter media.

Development of technologies for air filtration and purification is critical to meet the global challenges of threatened human health and accelerated greenhouse effect, especially for point-of-use applications. Here, we report a novel electreted polyetherimide–silica (PEI–SiO2) fibrous membrane by a single-step strategy to achieve effective filtration of fine particles. The hierarchical structured PEI–SiO2 membranes were endowed with promising superhydrophobicity with a water contact angle of 152°, allowing their better self-cleaning performance compared with commercial polypropylene (PP) filter media. Morphology, electric charge property, porous structure, and filtration performance could be regulated by tuning the type and concentration of electrets as well as the solution properties. Furthermore, unlike the commercial PP-based filter media, the as-prepared membranes can be treated at 200 °C for 30 min without sacrificing filtration efficiency (99.992%) and pressure drop (61 Pa) owing to the combined contribution of polarization and space charges. We anticipate that this promising electreted fibrous medium will act as a core part of numerous air filtration systems, including ultra-low penetration air filters, clean room, respirator, and protective clothing.

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