The effect of topographic defects on the superhydrophobic properties of coatings based on ZnO

The results of a study of the hydrophobic properties of a ZnO coating with different morphologies of the surface are presented. It is shown that the Wenzel state is implemented for the case of samples of ZnO with nanoscale surface roughness, while the Cassie state is implemented for microstructured samples. A superhydrophobic state with a contact angle of 151$^\circ$ and work of adhesion of 8.82 mJ/m$^2$ is achieved for a sample with multimodal surface roughness. It is demonstrated that the presence of microscale defects on the surface of the superhydrophobic samples leads to the instability of the Cassie state, while the Cassie–Wenzel transition is fulfilled in the case of increasing the radius of water drops.