Investigation of effective parameters in the formation of nanoporous and regular anodized aluminum oxide structures

In this study, anodized aluminum oxide nanostructures were prepared by anodization process under constant potential in an oxalic acid solution that was improved with sulfuric acid. The effects of various parameters such as voltage, electrolyte solution composition, anodizing time and type of stripping solution of oxide layer on the morphology of prepared nanostructures were optimized and scanning electron microscopy images were obtained. According to the results, voltage 45 V as optimized voltage and oxalic acid improved with sulfuric acid as the best electrolyte solution were obtained. The optimized times for first and second anodizing steps were 60 and 240 minutes, respectively, and a mixture of phosphoric acid and chromic acid was as the perfect solution to dissolve the oxide layer. Nanopores in the prepared samples under optimum conditions had the higher average distance and interpore distance and the porosity was increased. Also, array and uniformity of the pore size were increased in these samples. These nanostructures with unique properties have special applications in the field of membrane, synthesized template for various nanostructures, sensors and biosensors.