Gamma-irradiation-driven fabrication of robust underwater superoleophobic nylon mesh for high-efficiency oil/water separation

The urgent need to address severe threats to marine ecosystems from industrial oil pollution and spills drives the development of efficient and robust oil/water separation technologies. Inspired by the anti-fouling mechanisms of marine algae, this study presents a gamma (γ)-irradiation-driven layer-by-layer (LbL) self-assembly strategy to construct a polyvinyl alcohol (PVA)/sodium alginate (SA)/calcium carbonate (CaCO 3 ) multi-layered nanocomposite coating on nylon mesh substrates. Synergistic Ca 2+ crosslinking and γ-irradiation-induced interpenetrating networks confer exceptional mechanical stability (tensile strength: 96.1   MPa, elongation at break: 91.8%) with robust anti-swelling properties. The micro-nano hierarchical surface achieves underwater superoleophobicity (underwater oil contact angle >150°). The PVA/SA/CaCO 3 mesh demonstrates >99% separation efficiency and flux of 1492   L·m -2 ·h -1 for diverse oil/water mixtures under gravity, maintaining 98.6% efficiency after 40 cycles. Mechanical stability persists in extreme environments including anhydrous ethanol, strong alkali (pH = 14), and high-salinity solutions (5   mol/L NaCl). A stable hydration layer enables self-cleaning and anti-fouling behavior, with zero oil adhesion during dynamic impact tests. Critically, solvent-free γ-irradiation without toxic agents, ensuring green fabrication. This work provides an efficient, durable, and environmentally friendly solution for oil/water separation under complex conditions, demonstrating significant potential for marine ecological remediation and industrial wastewater treatment.