Hierarchical Nano/Micro Moth Eyelike Polymer Film Using Solid/Liquid Interfacial Reaction at Room Temperature

A simple pathway for the fabrication of real moth eyelike patterned (MEP) polymer film with a double-layered nano/microhierarchical structure is demonstrated through a solid/liquid interfacial reaction at atmospheric conditions. A convex-structured polyvinyl alcohol (PVA) film containing CdCl₂ was first fabricated using a self-organized honeycomb-patterned porous film as a template. The CdCl₂/PVA convex film was immersed into Na₂S/ethanol solution to facilitate the reaction between CdCl₂ and Na₂S at the solid/liquid interface, which led to the functionalization of CdS nanoparticles in the convex-structured PVA film. The tunable introduction of interfacial reaction resulted in the formation of a CdS moth eyelike nanoarray on the top surface of the PVA convex microarray, which mimicked the real moth eye (PVA-CdS MEP). PVA-CdS MEP film with a double moth eyelike structure showed improved antireflective property in comparison with flat and convex-structured PVA films. The PVA-CdS MEP film showed photoresponse under simulated solar light radiation and flexible duration after 500 cycles of folding.