A facile route for the fabrication of a superhydrophilic and underwater superoleophobic phosphorylated PVA-coated mesh for both oil/water immiscible mixture and emulsion separation

Special wettable materials have been shown to be promising for use in oil-water separation and, in particular, hydrogel-based materials have been studied for water separation from oil-water mixtures due to their high hydrophilicity. Here, a superhydrophilic and underwater superoleophobic phosphorylated PVA (PPVA) hydrogel-coated stainless-steel mesh with underwater oil repellency was prepared using a simple and facile route that introduced metal ions for PVA crosslinking. The PPVA hydrogel-coated mesh can not only separate immiscible oil-water mixtures but also separate surfactant-stabilized oil-in-water emulsions with a high separation efficiency (>99.2%). In addition, due to its multiple crosslinked networks, the resultant PPVA hydrogel-coated mesh exhibited good chemical stability and wear resistance and can tolerate high acid, alkali, salty and organic solvents.