Highly-hydrophobic, transparent, and durable coatings based on ZnO tetrapods with diamond-like carbon nanocomposite

Abstract

This study investigates the wettability of ZnO tetrapod (ZnO-T) coatings in relation to surface morphology and protective diamond-like carbon nanocomposites with SiOx (DLC:SiOx) film parameters. Randomly distributed ZnO-Ts with different leg lengths were observed to have varying degrees of wettability, which also changed keeping samples in the dark at room temperature. DLC:SiOx films significantly increase the hydrophobicity of ZnO-T coatings, and their thickness influences the surface roughness and hydrophobicity of the coating, moreover DLC:SiOx films show protection not only from the abrasion but also passivate the ZnO-T coatings from light-induced effects. The results indicate that the largest size ZnO-T fraction with a 40 nm thickness of DLC:SiOx film can provide the best hydrophobicity represented by a water contact angle of 148°, while the smallest ZnO-T fraction with a 120 nm thickness of DLC:SiOx film can provide better mechanical durability. We expect that the detailed analysis of ZnO-T coatings with protective DLC:SiOx films conducted in this study will be advantageous for other nanostructures with protective coatings application in wettability control.