Recent trends in synthesis of nanoporous anodic aluminum oxides

Abstract Porous anodic aluminum oxide (AAO) with highly ordered pores is one of the most desirable morphologies in point of view of the practical applications. Scientists still develop new methods leading to obtaining the expected morphology and improving AAO properties. As it is already known, the architecture of AAO depends on anodization conditions (i.e., the composition of the electrolyte, temperature, voltage/current of anodization). In this chapter, novel procedures for the synthesis of AAO were presented and compared with commonly known conditions used for Al anodization so far. The anodic oxidations in alkaline, neutral and also less popular acid solutions (i.e., chromic, selenic, arsenic, malonic, pyrophosphoric, etidronic, and glutaric acids) were described in detail. Furthermore, it was also discussed how the addition of various substances such as ionic liquids, ethanol, polyethylene glycol, glycerin to the anodization electrolyte affects the morphology of formed AAOs. Finally, we presented other unusual conditions of anodic oxidation such as modified pulse, hybrid potential, or AC anodization.