A Comparative Study on the Wettability between Butterfly and Locust Wing Surface

2015 ◽  
Vol 1089 ◽  
pp. 181-184
Author(s):  
Gang Sun ◽  
Yan Fang

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.

2015 ◽  
Vol 1095 ◽  
pp. 593-597
Author(s):  
Gang Sun ◽  
Yan Fang

The microstructure, hydrophobicity and chemical composition of the locust and moth 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-Baxter equation. The locust and moth wing surfaces are composed of naturally hydrophobic materials, but exhibit different complex wettability. The locust wing surface is of extremely high adhesion (sliding angle>180°) and superhydrophobicity (contact angle 151.5~157.3°), while the moth wing surface is of low adhesion (sliding angle 1~3°) and superhydrophobicity (contact angle 150.5~155.6°). The complex wettability of the wing surfaces ascribes to the cooperative effect of material element and structural element. The locust and moth wings can be potentially used as biomimetic templates for design and preparation of novel functional interface and no-loss microfluidic transport channels.


2015 ◽  
Vol 723 ◽  
pp. 948-951
Author(s):  
Gang Sun ◽  
Yan Fang

The water-and methanol-repellent properties of moth wing surfaces were determined by a contact angle (CA) meter, the chemical composition and microstructures of moth wing surfaces were investigated by a Fourier transform infrared spectrometer (FT-IR) and a scanning electron microscope (SEM). The wing surface is composed of naturally hydrophobic material and possesses hierarchical rough structures. The wing surface exhibits high repellency against water (CA 139.2~155.6°) and methanol solution. The critical concentrations for wetting and spreading-wetting of methanol solution on the wing surfaces are 60% and 80%, respectively. The complex wettability of the wing surface ascribes to the coupling effect of chemical composition and micro/nanostructure. Moth wing can be used as a template for bionic design of special functional surface.


2015 ◽  
Vol 1089 ◽  
pp. 190-193
Author(s):  
Gang Sun ◽  
Yan Fang

The complex wettability, chemical composition and microstructure of locust wing surface were investigated by a video-based contact angle (CA) meter, a Fourier transform infrared spectrometer (FT-IR) and a scanning electron microscope (SEM). A model for hydrophobicity of wing surface was established on the basis of Cassie equation. The wetting mechanism was discussed from the perspective of biological coupling. The wing surface is a waxy layer composed mainly of long chain hydrocarbon, tallate and fatty-acid alcohol, possesses multiple-dimensional rough microstructures including primary structure (wing vein grids), secondary structure (regularly arraying micrometric pillar gibbosities), and tertiary structure (nanocorrugations). The diameter, height, and spacing of pillar gibbosity are 3.0~10.2 μm, 3.4~9.2 μm, and 7.5~18.5 μm, respectively. Locust wing surface is of high adhesive superhydrophobicity (CA 150.1~157.3°). The complex wettability of the wing surface ascribes to coupling effect of material element (waxy crystal) and structural element (hierarchical rough microstructure). Locust wing can be potentially used as a biomimetic template for design of special functional surface. This work may bring insights for preparation of micro-controllable superhydrophobic surface and no-loss microfluidic channels.


2015 ◽  
Vol 1089 ◽  
pp. 198-201
Author(s):  
Gang Sun ◽  
Yan Fang

The microstructure, hydrophobicity, adhesion and chemical composition of the butterfly and the moth wing surfaces were investigated by a scanning electron microscope (SEM), a contact angle (CA) meter, and a Fourier transform infrared spectrometer (FT-IR). Using ground calcium carbonate (heavy CaCO3) as contaminating particle, the self-cleaning performance of the wing surface was evaluated. The wing surfaces, composed of naturally hydrophobic material (chitin, protein, fat, etc.), possess complicated hierarchical micro/nanostructures. According to the large CA (149.5~156.9° for butterfly, 150.5~155.6° for moth) and small sliding angle (SA, 1~3°), the wing surface is of low adhesion and superhydrophobicity. The removal rate of contaminating particle from the wing surface is averagely 88.3% (butterfly wing) and 88.0% (moth wing). There is a good positive correlation (R2=0.8152 for butterfly, 0.8436 for moth) between particle removal rate and roughness index of the wing surface. The coupling effect of material element and structural element contributes to the outstanding superhydrophobicity and self-cleaning performance of the wing surface. The wings of Lepidoptera insect can be potentially used as templates for biomimetic preparation of intelligent interfacial material with multi-functions.


2015 ◽  
Vol 1089 ◽  
pp. 194-197
Author(s):  
Gang Sun ◽  
Yan Fang

The microstructure, hydrophobicity, adhesion, and chemical composition of moth wing surfaces were investigated by a scanning electron microscope (SEM), a contact angle (CA) meter, and a Fourier transform infrared spectrometer (FT-IR). Using ground calcium carbonate (heavy CaCO3) as contaminating particle, the self-cleaning performance of wing surface was evaluated. The self-cleaning mechanism was discussed from the perspective of biological coupling. The wing surfaces, composed of naturally hydrophobic material (chitin, protein, fat, etc.), possess complicated hierarchical micro/nano structures. According to the large CA (138.9~158.4°) and small sliding angle (SA, 1~3°) of water droplet, moth wing surface is of low adhesion and high hydrophobicity. The removal rate of contaminating particle from wing surface is averagely 83.8%. There is a good positive correlation (r=0.81) between particle removal rate and roughness index of wing surface. The coupling effect of material element and structural element leads to the remarkable hydrophobicity and self-cleaning property of the wing surface. Moth wing can be potentially used as a template for biomimetic design of functional material with complex wettability. This work may offer interesting inspirations for preparation of smart interfacial material.


2015 ◽  
Vol 1095 ◽  
pp. 608-611
Author(s):  
Yan Fang ◽  
Gang Sun

The microstructure, superhydrophobicity and chemical composition of the moth wing surface were investigated by a scanning electron microscope (SEM), an optical contact angle (CA) meter and a Fourier transform infrared spectrometer (FT-IR). nanosilver film was coated on the wing surface by vacuum evaporation. The wetting mechanism was discussed from the perspective of biological coupling. The moth wing surface, composed of naturally hydrophobic material, is of high hydrophobicity (CA 143~156°) and exhibits complicated hierarchical micro-morphology including primary structure, secondary structure and tertiary structure. The cooperation of hydrophobic material and rough micro-morphology leads to the high hydrophobicity of the wing surface. The wing surfaces coated with 50~1000 nm silver films are still hydrophobic (CA > 110°). The multiple-dimensional rough structure of the wing surface results in the transition of metal silver from hydrophilic to hydrophobic. The moth wing can serve as a bio-template for design and preparation of micro-controllable superhydrophobic surface.


2015 ◽  
Vol 727-728 ◽  
pp. 3-6 ◽  
Author(s):  
Gang Sun ◽  
Yan Fang

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.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seyed Mehran Mirmohammadi ◽  
Sasha Hoshian ◽  
Ville P. Jokinen ◽  
Sami Franssila

AbstractA polydimethylsiloxane (PDMS)/Cu superhydrophobic composite material is fabricated by wet etching, electroless plating, and polymer casting. The surface topography of the material emerges from hierarchical micro/nanoscale structures of etched aluminum, which are rigorously copied by plated copper. The resulting material is superhydrophobic (contact angle > 170°, sliding angle < 7° with 7 µL droplets), electrically conductive, elastic and wear resistant. The mechanical durability of both the superhydrophobicity and the metallic conductivity are the key advantages of this material. The material is robust against mechanical abrasion (1000 cycles): the contact angles were only marginally lowered, the sliding angles remained below 10°, and the material retained its superhydrophobicity. The resistivity varied from 0.7 × 10–5 Ωm (virgin) to 5 × 10–5 Ωm (1000 abrasion cycles) and 30 × 10–5 Ωm (3000 abrasion cycles). The material also underwent 10,000 cycles of stretching and bending, which led to only minor changes in superhydrophobicity and the resistivity remained below 90 × 10–5 Ωm.


2010 ◽  
Vol 663-665 ◽  
pp. 894-897
Author(s):  
Hua Huang ◽  
Hai Hu Yu ◽  
Ling De Zhou ◽  
Er Dan Gu ◽  
De Sheng Jiang

Hybrid Graphene-ZnS nanopaticles (G-ZnS NPs) were prepared by using a solvothermal method. A dispersion of graphite oxide (GO) and zinc acetate dihydrate (Zn(CH3COO)2.2H2O) in dimethl sulfoxide (DMSO) reacted at 180 °C for 12 h in a Telfon-lined stainless steel autoclave. In the reaction, DMSO serves as a sulphide source as well as a reducing agent, resulting formation of the hybrid G-ZnS NPs in one-step. Hybrid G-ZnS NPs were characterized by using a powder X-ray diffractometer, a Fourier-transform infrared spectrometer, a transmission electron microscope, a UV-vis spectrophotometer and a fluorescence spectrophotometer, respectively. In the FTIR spectra, the GO related stretching bands of C-O and carboxyl groups are not observed in the spectra of G-ZnS, suggesting that the GO sheets were reduced to graphene sheets. In the TEM images, it is observed that the ZnS nanoparticles with an average size of 23 nm are attached onto the graphene sheets. The UV-vis absorption spectrum of the G-ZnS NPs dispersed in ethanol has an absorption peak of G at 261 nm and a weak shoulder of ZnS NPs around 320 nm. The broadening and weakening of the peak of ZnS NPs at 320 nm arises from the interparticle coupling effect. Under excitation at 225 nm, a peak around 386 nm and other weaker bands appear in the fluorescence spectrum of the G-ZnS. The band at 386 nm is attributed to zinc vacancies.


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