A Comparison of the Complex Wettability between Locust and Moth Wing

2015 ◽  
Vol 1095 ◽  
pp. 593-597
Author(s):  
Gang Sun ◽  
Yan Fang
Keyword(s):  
Contact Angle ◽  
Wing Surface ◽  
Baxter Equation ◽  
Structural Element ◽  
Sliding Angle ◽  
High Adhesion ◽  
Material Element ◽  
Infrared Spectrometer ◽  
Transport Channels ◽  
Functional Interface

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.

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

2015 ◽  
Vol 1089 ◽  
pp. 181-184
Author(s):  
Gang Sun ◽  
Yan Fang
Keyword(s):  
Contact Angle ◽  
Coupling Effect ◽  
Wing Surface ◽  
Functional Surface ◽  
Sliding Angle ◽  
High Adhesion ◽  
Infrared Spectrometer ◽  
Ft Ir ◽  
Transport Channels ◽  
Locust Wing

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.

Self-Cleaning Characteristic of the Insect (Lepidoptera) Wing Surfaces

2015 ◽  
Vol 1089 ◽  
pp. 198-201
Author(s):  
Gang Sun ◽  
Yan Fang
Keyword(s):  
Coupling Effect ◽  
Removal Rate ◽  
Wing Surface ◽  
Particle Removal ◽  
Structural Element ◽  
Sliding Angle ◽  
Cleaning Performance ◽  
Material Element ◽  
Infrared Spectrometer ◽  
Self Cleaning

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.

Low Adhesive Superhydrophobicity and Self-Cleaning Property of Moth Wing

2015 ◽  
Vol 1089 ◽  
pp. 194-197
Author(s):  
Gang Sun ◽  
Yan Fang
Keyword(s):  
Coupling Effect ◽  
Removal Rate ◽  
The Self ◽  
Wing Surface ◽  
Particle Removal ◽  
Structural Element ◽  
Sliding Angle ◽  
Material Element ◽  
Infrared Spectrometer ◽  
Self Cleaning

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.

High Adhesive Superhydrophobicity and Wetting Mechanism of Locust Wing Surface

2015 ◽  
Vol 1089 ◽  
pp. 190-193
Author(s):  
Gang Sun ◽  
Yan Fang
Keyword(s):  
Tertiary Structure ◽  
Coupling Effect ◽  
Wing Surface ◽  
Microfluidic Channels ◽  
Functional Surface ◽  
Structural Element ◽  
Wing Vein ◽  
Material Element ◽  
Infrared Spectrometer ◽  
Locust Wing

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.

scholarly journals Fabrication of elastic, conductive, wear-resistant superhydrophobic composite material

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seyed Mehran Mirmohammadi ◽  
Sasha Hoshian ◽  
Ville P. Jokinen ◽  
Sami Franssila
Keyword(s):  
Contact Angle ◽  
Composite Material ◽  
Contact Angles ◽  
Wet Etching ◽  
Sliding Angle ◽  
Electrically Conductive ◽  
Wear Resistant ◽  
Nanoscale Structures ◽  
Mechanical Abrasion ◽  
Mechanical Durability

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.

Contact Angle of Nepenthes alata Slippery Zone: Results from Measurement and Model Analysis

2021 ◽  
pp. 1-7
Author(s):  
Lixin Wang ◽  
Pan Pan ◽  
Shixing Yan ◽  
Shiyun Dong
Keyword(s):  
Contact Angle ◽  
Hierarchical Structures ◽  
Model Analysis ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Structure Characteristic ◽  
Baxter Equation ◽  
Measured Contact Angle ◽  
The Relationship ◽  
Contact Angle Analysis

The slippery zone of Nepenthes alata depends on its highly evolved morphology and structure to show remarkable superhydrophobicity, which has gradually become a biomimetic prototype for developing superhydrophobic materials. However, the mechanism governing this phenomenon has not been fully revealed through model analysis. In this paper, the superhydrophobicity of slippery zone is studied by contact angle measurement, morphology/structure examination and model analysis. The slippery zone causes ultrapure water droplet to produce a considerably high contact angle (155.11–158.30°), and has a micro-nano scale hierarchical structures consisting of lunate cells and wax coverings. According to the Cassie-Baxter equation and a self-defined infiltration coefficient, a model was established to analyze the effect of structure characteristic on the contact angle. Analysis result showed that the calculated contact angle (154.67–159.49°) was highly consistent with the measured contact angle, indicating that the established model can quantitatively characterize the relationship between the contact angle and the structure characteristic. Our study provides some evidences to further reveal the superhydrophobic mechanism of Nepenthes alata slippery zone, as well as inspires the biomimetic development of superhydrophobic surfaces.

Effects of Nano Silver Film on the Hydrophobicity of Moth Wing

2015 ◽  
Vol 1095 ◽  
pp. 608-611
Author(s):  
Yan Fang ◽  
Gang Sun
Keyword(s):  
Silver Film ◽  
Tertiary Structure ◽  
Wing Surface ◽  
Optical Contact ◽  
Silver Films ◽  
Biological Coupling ◽  
Infrared Spectrometer ◽  
Ft Ir ◽  
Micro Morphology ◽  
Hydrophobic Material

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.

Enhancing the Strengths of Adhesion Bonds Between Composite Surface and Coating via UV Treatments

2017 ◽  
Author(s):  
R. Asmatulu ◽  
K. S. Erukala ◽  
M. M. Rahman
Keyword(s):  
Contact Angle ◽  
Uv Radiation ◽  
Uv Light ◽  
Composite Coatings ◽  
Weight Ratio ◽  
High Strength ◽  
Water Contact ◽  
Composite Surface ◽  
Adhesion Properties ◽  
Infrared Spectrometer

Field of composites is rapidly growing in many industries such as aviation, energy and automotive industries. Composites are known to have a high strength to low weight ratio. Significant improvement in the performance of coatings used in the protection of military and civil aircraft has been achieved the last thirty years. Composite coatings are exposed to many environmental conditions, which can significantly affect their properties. In this research, UV light treatment on the surface of composite was introduced to examine its effects on the adhesion properties between the coating and substrate. A cross-cut test was conducted on the composite panels to assess the adhesion of paint to the substrate after the treatments. Coating performance analyses were also carried out using a Fourier transform infrared spectrometer, water contact angle, and optical microscopic images. The first set of panels was treated with UV radiation for 0, 2, 4 and, 8 days, and the surface wettability was also assessed using the contact angle test. Two coats of paints, including a primer and top coat, were used, and the panels were exposed to UV radiation and immersed in water for 500 hrs and 1000 hrs. It was found that untreated panels showed a much higher contact angle of 106°, whereas the contact angle of panels treated with UV radiation was reduced to 47°. The cross-cut tests showed considerable flaking of the coating along the edges and squares of panels that were not treated, and very small flakes along the edges and parts of the grid square on panels that were UV treated, thus confirming the enhancement of coating adhesion between composite and coating surfaces by UV treatments.

scholarly journals Investigations on the execution and evaluation of the Pummel test for polyvinyl butyral based interlayers

2020 ◽  
Vol 5 (3) ◽  
pp. 371-396
Author(s):  
Miriam Schuster ◽  
Jens Schneider ◽  
Tuong An Nguyen
Keyword(s):  
Film Surface ◽  
Polyvinyl Butyral ◽  
Test Method ◽  
Structural Element ◽  
Binary Images ◽  
Free Film ◽  
Safety Glass ◽  
High Adhesion ◽  
Adhesion Level ◽  
Pull Tests

Abstract Laminated safety glass (LSG) is increasingly used as structural element in buildings. Of central importance for safety are the adhesion and the residual load-bearing capacity in the post fractured state. In literature a large number of tests to assess adhesion is mentioned. These include, e.g. peel tests, through-cracked-tensile/-bending tests, VW-pull tests and compressive shear tests. However, especially in industry, the Pummel test is widespread for determining the quality of adhesion in LSG with polyvinyl butyral based interlayers. This test method proves to be simple and quick to carry out: The laminate is stored at − 18 °C and then completely destroyed at room temperature with hammer blows. The adhesion level (0–10) is determined by visually comparing the adhering glass fragments with reference pictures or with the help of diagrams and tables which indicate the Pummel value as a function of the free film surface. Pummel value 0 is to be interpreted as no adhesion and Pummel value 10 as very high adhesion. Due to the lack of standardization, the execution and evaluation is very much dependent on the test institution and executive person. This paper shows different Pummel classifications that can currently be found on the market. Subsequently, approaches to the automatization and standardization of the execution and especially the evaluation of the Pummel test are shown. Three image evaluation methods in Matlab are presented, discussed and compared: (1) analysis of binary images, (2) statistical evaluation of the greyscale images and (3) texture analysis using co-occurrence matrices.

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