Study on the structure-activity relationship between oil dewetting self-cleaning and surface morphology for crude oil pollution treatment and crude oil/water separation

The oil dewetting self-cleaning performance is the most effective method to solve viscous oil pollution. The surface composition has a positive correlation with the property, and oil droplets tend to desorb on highly hydrophilic surfaces. But the influence of surface microstructure is more complex. Herein, we prepared a variety of surface structures with different morphologies and parameters, and performed the same surface modification to ensure compositional homogeneity. By testing the oil dewetting performance, we found that the surface microstructure has two modes of action: promotion and inhibition, and the final effect depends on the relative strength. The former comes from the amplifying effect of the structure on the wettability, and the latter refers to the hindering effect of the structure on the movement of oil droplets. The UOWCA reached 0 degrees for the nanowire and honeycomb structures, and the oil droplets could quickly detach from the surface of the honeycomb structure in about 5 s. When the deposition of nanoparticles on the surface reaches 4 layers, the oil droplets can desorption from the surface within 2 min. The nanoparticle-deposition and the honeycomb structure also exhibit excellent crude oil pollution cleaning and crude oil-water separation ability. This study can not only provide two kinds of structures for crude oil treatment in practice, but also help us deeply understand the structure-activity relationship between surface morphology and oil dewetting performance in theory.