Bioinspired spindle-knotted structure fiber membrane prepared by modified coaxial electrospinning for water-in-oil emulsion separation

Inspired by the conformation of spider silks, fibers with multiscale spindle-knotted structures were fabricated via a one-step modified coaxial electrospinning method. Under a high-voltage electric field, hydrophobic silica polystyrene (PS) fibers coated poly (methyl methacrylate) (PMMA) fibers were integrated together during the electrospinning process. Due to the addition of hydrophobic gaseous SiO 2 combining the spindle structure, a superhydrophobic fibrous membrane was prepared, and the bioinspired fibers achieved a superhydrophobic/superoleophilic performance for efficient emulsion separation. The results demonstrate that the incorporation of PS and SiO 2 improved the efficiency of emulsion separation of the fabricated fibrous membranes by optimizing microstructure and wettability: Specifically, an extraordinary water contact angle under oil (162°) and a satisfied oil contact angle under water (0°). For water-in-diesel emulsions, a high separation efficiency of 99.1% was obtained for membrane with PS addition of 4 wt%, which is greater than of pure PVDF membrane with SiO 2 (75.5%). It performs better than most other membranes showing strong promise in grease purification and oily wastewater treatment.