Preparation of moth-eye structures on curved surfaces by nanoimprinting using anodic porous alumina molds

Al substrates with smooth curved surfaces were fabricated by peeling off Al foil sputtered on the surface of concaved substrates. Anodic porous alumina with tapered pores on the curved surface was obtained by repeated anodization and etching of the obtained Al substrate. The moth-eye structure was formed on the curved surface by nanoimprinting using the anodic porous alumina as a mold. From the reflectance measurement, it was shown that the reflection of the incident light was suppressed on the curved surface where the moth-eye structure was formed. This process can be used to fabricate moth-eye structures on the surface of substrates of various shapes by changing the substrate used for sputtering and is expected to expand the range of applications for moth-eye structures.