Superhydrophobicity–superoleophilicity patterns, which have shown significant potential in surface science, have significant applications in oil–water separation. In this regard, the design of an optimal pattern with controlled roughness to increase the separation efficiency has, however, remained a challenge. In this study, a superhydrophobic–superoleophilic coating on a fabric-based substrate was prepared by utilizing a dielectric barrier discharge (DBD) in layer-by-layer assembly. To access a high separation efficiency, the optimum roughness was provided by the proper distribution of ZnO nanoparticles beneath the diamond-like carbon coating. Chemical and morphological features, as well as other properties of the deposited coating, were characterized through XPS, FTIR, FESEM, and AFM assay. An increase was observed in the static water contact angle of the superhydrophobic coating to 166°, while the surface roughness was enhanced from 9.84 to 38.19 nm. Moreover, the diesel oil/water separation test demonstrated enhancement of the surface roughness with no negative impact on the flow passage. NPs reinforced the DLC coating separation properties by which the separation efficiency of nearly 99% was achieved. The present research could offer a feasible method and environmentally friendly technique for the fabrication of coatings for oil removal from contaminated water.
