A Comparative Study on the Wettability between Butterfly and Locust Wing Surface
The microstructure, hydrophobicity and chemical composition of the butterfly and locust wing surfaces were investigated by a scanning electron microscope (SEM), a contact angle meter and a Fourier transform infrared spectrometer (FT-IR). The hydrophobicity models were established on the basis of the Cassie equation. The wetting mechanism was comparatively discussed from the perspective of biological coupling. The butterfly and the locust wing surfaces are composed of naturally hydrophobic materials, but exhibit different complex wettability. The butterfly wing surface is of low adhesion (sliding angle 1~3°) and superhydrophobicity (contact angle 151.6~156.9°), while the locust wing surface is of extremely high adhesion (sliding angle>180°) and superhydrophobicity (contact angle 155.8~157.3°). The complex wettability of the wing surfaces ascribes to the coupling effect of hydrophobic material and rough structure. The butterfly and locust wings can be used as bio-templates for design and preparation of biomimetic functional surface, intelligent interfacial material and no-loss microfluidic transport channels.