Synthesis of Porous Anodic Alumina Featuring a Periodic Pore Structure by Regulating the Anode Temperature

Porous anodic alumina (PAA) with a periodic pore structure has been synthesized by using an innovative preparation method. The morphology of PAA pores can be modulated within the same electrolyte by adjusting the temperature of the aluminum anode, enabling periodic variations in pore size ( D p ). The formation mechanism of PAA has been elucidated through analyses of micromorphology, anodization current density ( i a ), interpore distance ( D int ), and D p of the samples. Results indicate that the average D int for the synthesized PAA is approximately 260–340 nm, while the average D p ranges from 90 to 260 nm. Both i a and D p exhibit periodic fluctuations corresponding to changes in anode temperature under consistent electrolyte conditions and anodization voltage ( U a ). Lateral pores are generated via a phosphoric acid etching process, resulting in PAA with a distinctive three-dimensional interconnected pore architecture. Furthermore, ridges with an arc-like shape on the outer walls of PAA pores have been observed; their formation mechanism can be effectively explained by the convection model and the viscous flow model. These findings contribute significantly to achieving precise control over the pore structure of PAA.