Fabrication of novel superhydrophilic/underwater superoleophobic composite coatings and study on the relationship between their long-term wettability and excellent oil-water separation performance

A superhydrophilic/underwater superoleophobic composite coating ([email protected]) was fabricated through etching and subsequent modification of stainless steel mesh (SSM). It had a water contact angle of 0° in the air, an oleophobic angle of 162.7° underwater, and a sliding angle of 5°. Even after 15 days, the separation efficiency of crude oil-water was up to 98.6% and had a high water flux of 13535 L m−2 h−1. After 50 sandy impacts, the [email protected] had an oil contact angle of 158.5° and sliding angles of 13° underwater. Experimental results show that the water flux and the contact angle were closely related, and there was a negative correlation between the water flux and the water contact angle. Furthermore, the [email protected] was featured with long-term stability, chemical stability and excellent mechanical stability. Apart from that, it has potential application value in the field of oil and water treatment.