Double‐Sided Electrostatically Spun Fiber Membrane Fabricated by A‐Side: Ag@PDA/PEN‐BPA, B‐Side: TiO ₂ /PEN‐B/P for Oil‐Water Separation with Performance of Antimicrobial and Photocatalytic Self‐Cleaning in Harsh Environments

Abstract Separating oil‐water emulsions in harsh conditions poses a substantial challenge for filtration membrane systems. In response, this study presented a continuous electrospinning technique to fabricate a robust bifacial composite membrane. Two types of high‐performance polyarylene ether nitrile (PEN) polymers, PEN‐BPA and PEN‐B/P, with different wettability, are employed to construct the AB bifacial structure. Further, the A‐side is modified with hydrophilic polydopamine (PDA) and antibacterial silver nanoparticles (Ag NPs) to prepare Ag@PDA/PEN‐BPA, while the B‐side is altered with photocatalytic titanium dioxide nanoparticles (TiO 2 ) to prepare TiO 2 /PEN‐B/P. The resulting Ag@PDA/PEN‐TiO 2 /PEN‐B/P bifacial membrane demonstrates remarkable photocatalytic degradation efficiency, particularly for MB, reaching 99.8% degradation efficiency. Moreover, the permeation flux and oil‐water emulsion separation rejection rate of the membrane reach 5180.34 L m − 2 ·h −1 and 99%. The PEN substrates are not only used to construct the AB bifacial structure but also to enhance the membrane's toughness and durability, ensuring stability in high‐temperature and corrosive environments, with a rejection rate reaching 99% after 10 reuse cycles. Furthermore, integrating Ag NPs imparts excellent antibacterial properties to the membrane, sustaining a 99.99% antibacterial rate after oil‐water emulsion separation, photocatalytic dye degradation, and exposure to high‐temperature NaCl immersion. This study offers novel insights into multifunctional water treatment materials in harsh environments.