Qian Cong Key Laboratory of Bionic Engineering (Jilin University), Ministry of Education, P.R.China
The surface shape, structure, biomaterial and wettability of Lepidoptera insect wings (Butterflies and moths) were qualitatively and quantitatively studied by means of a stereoscopic microscope, a scanning electronic microscope, fourier transform infrared spectroscopy(FT-IR) and the interface contact angle measurement. The observation shows that Lepidoptera insect wings'surface has stronger hydrophobicity. There are scales arranged like overlapping tiles on the surface of the wings. The shapes of the scales are different between species. The surface of the scale is structured by grooves and vertical gibbosities. The length of butterfly wing scale is 65~150μm,width 35~70μm,distance 48~91μm. The height of vertical gibbosity on wing scale is 200~900 nm,width 200~840 nm,distance 1.06~2.74μm.The length of moth wing scale is 121~454μm,width 44~182μm,distance 18~145μm. The height of vertical gibbosity on wing scale is 257~1971 nm , width 171~457 nm , distance 971~2946μm . The biomaterial components of the wing scale are mostly made up of protein, lipids and chitin. The observation also shows that the surfaces of the wings with scales are more hydrophobic. For example, the contact angle for wings with scales is in the range from 144.8° to 152.9°, while that those without scales is from 90.0° to 115.9°. According as Cassie model, the equation of wettability on Lepidoptera insect wing surface is established and the hydrophobic mechanism is analyzed. It is concluded that the hydrophobicity of Lepidoptera insect wings is induced by the multivariate coupling of the shape, structures and biomaterial of the scales.
Lepidoptera insect wings, Moth, Butterfly, Scale, Hydrophobicity, Biomaterial, Shape, Structure, Coupling
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