Patterned anodic aluminium oxide fabricated with a Ta mask

Abstract

Electrochemical anodization was applied to an aluminium (Al) sheet patterned with a metallic tantalum (Ta) mask, which gave rise to the formation of patterned anodic aluminium oxide (AAO). The morphological evolution of the AAO porous structure with anodizing time was characterized by scanning electron microscopy. Lateral anodizing of the Al sheet gradually developed underneath the metallic Ta mask with the increase of anodizing time. This has given us further understanding of the Al anodizing behaviour compared with our previous work with a SiO2 masked Al sheet. By controlling the anodizing time and the size of the metal mask, deep lithography of the Al substrate can be realized, and a mushroom-like Ta–Al microstructure with a high aspect ratio was created on the Al surface after removal of the AAO film. This Ta–Al microstructure has been studied in detail, and it was found to exhibit pronounced hydrophobic properties.

Highly Ordered Anodic Porous Alumina Formation by Self‐Organized Anodizing

“…The formation of ordered anodic porous alumina from the aluminum surface covered with a metallic Ta mask was also presented [440].…”

“…During the self-organized anodizing of aluminum, the process of pore nucleation is a combination of random nucleation and nucle- ation at surface faults. Moreover, the grain boundaries and scratches on the aluminum surface are sites for preferential pore development [440]. The pre-treatment process control must be focused on the reduction of surface faults, or on their controlled and reproducible generation, in the required morphology.…”

Fabrication of anodic aluminum oxide on silica optical fiber with nanopore channels oriented off surface normal

“…It has been reported that the orientation of the nanopore channels in AAO can be directed away from surface normal by putting aluminum in tension parallel to surface. 10 In addition, curved and dendritic pore channels can also be made by controlling the surface topography of aluminum 11,12 or with the aid of a patterned mask. 12 There have been no literature studies on the fabrication of AAO with uniformly aligned nanopore arrays off surface normal.…”

Preparation of a superhydrophobic rough surface

“…This state describes a droplet of water that fills the cavities of a rough surface and remains even when the surface is tilted to a high angle to clean the surface. In contrast, according to the Cassie–Baxter approach, a water droplet sits on top of the protuberances and does not fill the cavities, regardless of the roughness 17, 18. For example, water sits on the solid protuberances, whereas air fills the pockets of the rough surface.…”