Hierarchical super-hydrophobic coating with productive etching process and self-assembled Ag mask

Abstract Optical coating to maintain clear views in harsh environments is a vital technology to meet the increasing demand for vision assistance cameras or fully automated vehicles. In this study, the hierarchical nanostructured super-hydrophobic coating was fabricated without an expensive lithography process. First, the self-assembled Ag nano-mask was deposited on top of the SiO 2 layer instead of a lithography-patterned nano-mask. Next, isotropic etching to carve the SiO 2 layer and anisotropic etching to reshape the Ag nano-mask were alternatively applied to create a well-controlled hierarchical nanostructure of SiO 2 in one process. The size and pitch of the nanostructure were optimized by the deposition condition of Ag and the etching condition of Ag to gradually re-shape the Ag mask during the etching process. These techniques have achieved a productive etching process to form a rigid hierarchical nanostructure on a lens surface without a lithography technique.