One-step fabrication of superhydrophobic-superoleophilic membrane by initiated chemical vapor deposition method for oil-water separation

In this study, poly(1H,1H,2H,2H-perfluorodecyl acrylate) (PPFDA) thin films were deposited on stainless steel meshes by initiated chemical vapor deposition (iCVD) method to prepare superhydrophobic-superoleophilic membranes for oil-water separation. FTIR and XPS analyses showed high retention of the fluorine moieties, which are responsible for the superhydrophobic property of the as-deposited films. The measured water contact angle (WCA) values were observed to be dependent on the mesh size and the coating thickness. The maximum WCA value of the stainless steel mesh after iCVD was measured as 166.9 degrees, while oil contact angle value being nearly zero. Hence, iCVD of PPFDA on mesh surfaces created composite structures which were water-repellent but oil-permeable. iCVD-coated meshes were directly used for oil-water separation without using an extra force or chemical reagent. A high separation efficiency value of 98.5% was observed, the value of which was dependent on the mesh size and coating thickness.