Mussel-inspired chemistry and Michael addition reaction for efficient oil/water separation

An oil/water separation mesh with high separation efficiency and intrusion pressure of water has been successfully developed by combining mussel-inspired chemistry and Michael addition reaction. The substrate of the stainless steel mesh was first coated with the adhesive polydopamine (PDA) film by simple immersion in an aqueous solution of dopamine at pH of 8.5. Then n-dodecyl mercaptan (NDM) was conjugated with PDA film through Michael addition reaction at ambient temperature. The as-prepared mesh showed highly hydrophobicity with the water contact angle of 144° and superoleophilicity with the oil contact angle of 0°. It can be used to separate a series of oil/water mixtures like gasoline, diesel, etc. The separation efficiency remains high after 30 times use (99.95% for hexane/water mixture). More importantly, the relatively high intrusion pressure (2.2 kPa) gives the opportunity to separation of large amount of oil and water mixtures. This study provides a new prospect to simply introduce multiple molecules on the adhesive PDA-based mesh to achieve various functional oil/water separation materials.