Zwitterionic Polymer Hairy Coating onto Mesh toward Easy Oil/Water Separation

A zwitterionic polymeric hair-coated stainless steel mesh membrane is fabricated, which demonstrates efficient separation of oil/water mixtures and emulsions. The hairy coating of poly(divinylbenzene-co-vinylbenzene chloride) is generated by precipitation cationic polymerization, and subsequently grafting a zwitterionic polymer layer by atom transfer radical polymerization of sulfobetaine methacrylate. The microstructure of the hairy coating is tunable from an array of individual nanofibers to porous networks by interweaving of the hairs. The long-range attraction of zwitterionic polymers with water renders the coated mesh with excellent superhydrophilic and underwater superoleophobic performance. The coated mesh is highly antifouling to avoid the prehydration in conventional methods. Moreover, the microstructure is demonstrated to be responsible for the high separation efficiency of oil/water emulsion. Therefore, separation of oil/water mixtures and emulsions becomes easier by the coated mesh, which is promising in industrial oil field sewage treatment.