Porous Alumina with Shaped Pore Geometries and Complex Pore Architectures Fabricated by Cyclic Anodization

A study was conducted to demonstrate a new and generic anodization process, called cyclic anodization for controlled 3D structuring of porous anodic alumina oxide (AAO) with modulated pore geometries and complex pore architectures. The cyclic anodization concept was based on slow and oscillatory changes of anodization conditions that combined MA and HA anodization. It was demonstrated that it was possible to perform structural modulation of AAO and control the geometry of pore structures by applying periodic oscillatory current signals during annodization with different profiles, amplitudes, and periods. AAO with asymmetrical and symmetrical pore geometries with different lengths, periodicity, and gradients were fabricated by changing the profile, amplitude, and period of the current signal. The results show that the transformation of the current profile into structural pore features can be achieved by the anodization method.