The effect of propylene glycol on the optical properties of iridescent porous anodic alumina films

Abstract

Porous anodic alumina films with structural colors were successfully prepared in the mixed electrolyte which was the phosphoric acid of 0.6 M/L added with propylene glycol at 100 V and − 5 °C. In the experiment, by changing the electrolyte composition, the anodization rate of the film was controlled, and thus a precise adjustment to the structural colors of the films was achieved and, as a result, more intermediate colors were obtained. This study shows that the pore growth rate of the films during anodization can be greatly decreased by adding propylene glycol, and the reasons would be given in this paper. It was also discovered that the Au-coated thin layer helps to enhance the saturation of the film colors. These films show potential in many areas including decoration, display, anti-counterfeiting and so on.