Self-Ordered Porous Anodic Alumina with Large Pore Intervals: Review on Experimental and Theoretical Research


 The production of self-organized porous anodic alumina (PAA) with large intepore intervals (Dc > 380 nm) is still under development. The PAA is very interesting for applications in optics and photonics where a large-scale periodicity corresponding to visible or infrared light is required. However, the process remains challenging because it usually involves anodization under high voltages that is prone to instabilities and breakdown events. The basic problem relies on harnessing the electrochemical conditions to find a balance between various phenomena that occur during transformation from aluminum to porous alumina. The overall process is quite complicated but it is believed that regularity of pore formation is governed mainly by an equilibrated counter-ion (Al3+ and electrolyte anions A-) exchange at the electrolyte/oxide interface. Accordingly, a new concept of PAA growth is proposed which takes into account three basic elements of field-enhanced dissolution, plastic flow, and electro-convective models. The results on recent achievements in the high-voltage anodization is discussed focusing on the strategies that led to the self-ordering growth of PAA with large Dc. It is hoped that the review will contribute to better designing of anodization parameters to produce the ordered porous material with desired morphology.