Fabrication of Self-Ordered Porous Alumina via Etidronic Acid Anodizing and Structural Color Generation from Submicrometer-Scale Dimple Array

摘要

Highly ordered anodic porous alumina with a large-scale cell diameter was successfully fabricated viaanodizing in a new electrolyte, etidronic acid (1-hydroxyethane-1,1-diphosphonic acid). High-purityaluminum specimens were anodized in a 0.3 M etidronic acid solution under constant current densityand voltage conditions. Etidronic acid anodizing at 210 to 270 V at the appropriate temperature causedthe anodic porous alumina to exhibit self-ordering behavior, and periodic nanostructures measuring530 to 670 nm in cell diameter were fabricated on the aluminum substrate. The self-ordering voltage andthe corresponding cell diameter could be increased without burning by systematically increasing thestepwise voltage. Two-step etidronic acid anodizing without nanoimprinting can easily yield theformation of highly ordered anodic porous alumina with a large-scale cell diameter. A submicrometer-scale dimple array fabricated via etidronic acid anodizing and subsequent selective oxide dissolutiongave rise to bright structural color with a rainbow distribution.