Replication of surface nano-structure of the wing of dragonfly (Pantala Flavescens) using nano-molding and UV nanoimprint lithography

The hydrophobicity of a dragonfly's wing originates from the naturally occurring nano-structure on its surface. The nano-structure on a dragonfly's wing consists of an array of nano-sized pillars, 100 nm in diameter. We re-create this hydrophobicity on various substrates, such as Si, glass, curved acrylic polymer, and flexible PET film, by replicating the nano-structure using UV curable nano-imprint lithography (NIL) and PDMS molding. The success of the nano-structure duplication was confirmed using scanning electron microscopy (SEM). The hydrophobicity was measured by water-based contact angle measurements. The water contact angle of the replica made of UV cured polymer was 135A degrees +/- 2A degrees, which was slightly lower than that of the original dragonfly's wing (145A degrees +/- 2A degrees), but much higher than that of the UV cured polymer surface without any nano-sized pillars (80A degrees). The hydrophobicity was further improved by applying a coating of Teflon-like material.