Green and rapid fabrication of superhydrophilic and underwater superoleophobic coatings for super anti-crude oil fouling and crude oil-water separation

The development of surfaces with super anti-crude oil-fouling behavior and crude oil-water separation properties is still a global challenge owing to the high viscosity of crude oil. Herein, superhydrophilic and underwater superoleophobic surfaces were successfully prepared by a simple, green and environmentally friendly one-step dip coating method. In the whole process, microcrystalline cellulose with hydrophilic hydroxyl functional groups was introduced into the coating with the help of inorganic adhesives, water was the only solvent, and no other organic solvents or surface modifiers was added. Besides being highly resistant to low viscosity oils and achieving effective oil-water separation (more than 98.3% separation efficiency after 30 cycles), the surface effectively resisted crude oil adhesion and achieved high viscosity crude oil-water separation. In addition, the underwater oil contact angle can still reach 147.5 degrees and 152.5 degrees after 20 cycles of sandpaper friction tests and 50 cycles of finger pressure tests, respectively, which indicates excellent durability. Furthermore, the method can achieve excellent superhydrophilicity and underwater superoleophobicity on varieties of substrates (such as copper foil, aluminum sheet and glass), showing very extensive applicability. It is expected that such fabrication strategy can provide a low cost, green and environmentally friendly approach to construct a series of superhydmphilic and underwater superoleophobic surfaces to achieve super anti-crude oil-fouling and (crude) oil-water separation.

Automated summary

Superhydrophilic and underwater superoleophobic surfaces were successfully prepared using a one-step dip coating method by introducing microcrystalline cellulose with hydrophilic functional groups into the coating. The surface effectively resisted crude oil adhesion, achieved high viscosity crude oil-water separation, and exhibited excellent durability and extensive applicability.