Wetting in nanopores of cylindrical anodic aluminum oxide templates: Production of gradient polymer nanorod arrays on large-area curved surfaces

Although the fabrication of nanostructures has been investigated extensively, it is still a challenge to prepare nanostructures or nanostructure arrays on curved surfaces. In this work, we develop a simple and novel method to fabricate polymer nanorod arrays on large-area curved polymer surfaces with controlled curvatures. This method is based on the wetting of polymer melts in the nanopores of cylindrical anodic aluminum oxide templates, which are prepared by electrochemical anodization of aluminum wires. Polymers such as poly(methyl methacrylate) (PMMA) melts can wet the nanopores of the templates via capillary force after thermal annealing, resulting in the formation of PMMA nanorod arrays with gradient heights on curved PMMA surfaces. This work not only opens up new possibilities for creating non-planar surfaces with desired nanostructures, but also contributes to a deeper understanding of wetting behavior in confined geometries.