Synthesis and properties of iridescent Zn-containing anodic aluminum oxide films

• Iridescent PAA@Zn nanocomposite films were successfully fabricated.
• A simple organics-assisted method is applied to making a series of fancy and multicolor patterns.
• The color varies with the angle of incidence of the light used to view the film as is expected with Bragg–Snell formula.
• Such colored films could be used in multifunctional anti-counterfeiting applications.

A simple method of fabricating Zn-containing anodic aluminum oxide films for multifunctional anticounterfeit technology is reported. The resulting membranes were characterized with UV–vis illumination studies, natural light illumination color experiments, and electron microscopy analysis. Deposition of Zn in the nanopore region can enhance the color saturation of the thin alumina film with different colors dramatically. Both the anodization time and etching time have great influence on the structural color. The mechanisms for the emergence of this phenomenon are discussed and theoretical analysis further demonstrates the experimental results.