Fabrication of pre-wetting induced superamphiphobic meshes for on-demand oil-water separation of light or heavy oil-water mixtures

Abstract

In this study, a facile approach was proposed to fabricate superamphiphobic meshes for on-demand separating light or heavy oil and water mixtures after pre-wetting process. The micro-nano hierarchical structures on superamphiphobic stainless steel mesh were fabricated via vacuum thermal evaporation and chemical deposition. Low surface energy was acquired by modification with perfluorooctanoic acid. The effect of reaction time on wettability was investigated to obtain the optimal parameters of fabricating samples exhibiting superhydrophobicity and superoleophobicity simultaneously. The wettability of superamphiphobic meshes was controlled by the liquids of pre-wetting process. The superamphiphobic surfaces pre-treated with ethanol and water were used to separate the mixtures of light oil and water, while the meshes sequentially pre-soaked with ethanol and oil to separate the mixtures of heavy oil and water. The separation efficiency of up to 98 % was found even after multiple cycles. The fabricated superamphiphobic surfaces can avoid contamination and achieve on-demand oil-water separation without any external forces, which will have promising potential for application in oil-water separation.