Open Access Conference Proceedings

High-voltage nanoporous anodic films grown on aluminium in certain organic electrolytes are of increasing interest for potential applications as nanotemplates to electrical capacitors and, more generally, as models for investigating self-organized growth of anodic oxides at the frontier conditions. The major difficulty associated with this technology is that the process of pore nucleation and growth over a large-area aluminium substrate needs optimization and adaptation to the specific technological conditions applied to aluminium substrates as the surface finishing pre-treatments. In this work we have studied the impact of important pre-treatment technologies for Al foils, such as high temperature annealing and electrochemical polishing, on the pore nucleation and growth during galvanostatic formation of nanoporous anodic alumina templates in aqueous solutions of citric acid. It was revealed that the self-organized pore nucleation and growth is strictly dependent upon the anodizing setup, anodizing variables, surface morphology and crystalline structure of aluminium foils, which are additionally affected by the conditions of vacuum annealing and electropolishing pre-treatments. The findings are useful for growing well-ordered nanopores for non-lithographic formation of metal and metal-oxide nanostructures for advanced capacitor application.

Keywords: anodizing, citric acid, porous anodic alumina, nanostructure, capacitor

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