Twenty-nine species of butterflies were collected for observation and determination of the wing surfaces using a ScanningElectron Microscope(SEM).Butterfly wing surface displays structural anisotropism in micro-,submicro- and nano-scales.Thescales on butterfly wing surface arrange like overlapping roof tiles.There are submicrometric vertical gibbosities,horizontallinks,and nano-protuberances on the scales.First-incline-then-drip method and first-drip-then-incline method were used tomeasure the Sliding Angle(SA)of droplet on butterfly wing surface by an optical Contact Angle(CA)measuring system.Relatively smaller sliding angles indicate that the butterfly wing surface has fine self-cleaning property.Significantly differentSAs in various directions indicate the anisotropic self-cleaning property of butterfly wing surface.The SAs on the butterfly wingsurface without scales are remarkably larger than those with scales,which proves the crucial role of scales in determining theself-cleaning property.Butterfly wing surface is a template for design and fabrication ofbiomimetic materials and self-cleaningsubstrates.This work may offer insights into how to design directional self-cleaning coatings and anisotropic wetting surface.
Gang Sun~(1,2), Yan Fang~(1,2), Qian Cong~1, Lu-quan Ren~11. Key Laboratory of Terrain-Machine Bionics Engineering (Ministry of Education, China), Jilin University,Changchun 130022, P. R. China2. School of Life Science, Changchun Normal University, Changchun 130032, P. R. China
The micromorphologies of surfaces of several typical plant leaves were investigated by scanning electron micros-copy(SEM). Different non-smooth surface characteristics were described and classified. The hydrophobicity and anti-adhesion of non-smooth leaf surfaces were quantitatively measured. Results show that the morphology of epidermal cells and the mor-phology and distribution density of epicuticular wax directly affect the hydrophobicity and anti-adhesion. The surface with uniformly distributed convex units shows the best anti-adhesion,and the surface with regularly arranged trellis units displays better anti-adhesion. In contrast,the surface with randomly distributed hair units performs relatively bad anti-adhesion. The hydrophobic models of papilla-ciliary and fold-setal non-smooth surfaces were set up to determine the impacts of geometric parameters on the hydrophobicity. This study may provide an insight into surface machine molding and apparent morphology design for biomimetics engineering.
Lu-quan Ren Shu-jie Wang Xi-mei Tian Zhi-wu Han Lin-na Yan Zhao-mei Qiu
