Hydro-Oleophobic Property of Butterfly Wing Surface and Biomimetic Fabrication of Hydrophobic Silver Film

Abstract

The hydrophobicity and oleophobicity(methanol repellency) of butterfly wing surfaces were measured by a video-basedcontact angle (CA) meter. The multi-dimensional microstructure of the wingsurfaces was characterized by a scanning electron microscope (SEM) and an atomic force microscope (AFM). The wingsurface exhibits superhydrophobicity (water CA 150.4~159.2°) and low adhesion (water sliding angle 1~3°). Meanwhile, the wingsurface displays high repellency against methanol. The critical concentrationsfor wetting and spreading-wetting of methanol solution on the wing surface are60% and 80%, respectively. The butterfly wing surface is ofhydro-oleophobicity. The wing surface possessescomplicated hierarchicalmicrostructures. Using the butterfly wing as a bio-template, the hydrophobicsilver films were prepared. Water CA increases from metal silver’s intrinsicCA 63.0° maximally to 139.2° (Speyeria aglaja, 5 nm silver film). The microstructures on thewing surface result in the transition of metal silver from hydrophilic tohydrophobic. The butterfly wing can be used as a template for design of smartinterface and functional surface.