Wettability gradient on the elytra in the aquatic beetle Cybister chinensis and its role in angular position of the beetle at water-air interface

Sun, Mengtao; Chen, Yuan; Zheng, Yongmei; Zhen, Mingming; Shu, Chunying; Zhang, Dai; Liang, Ai‐Ping; Gorb, Stanislav N.

doi:10.1016/j.actbio.2017.01.022

Cited by 15 publications

(12 citation statements)

References 33 publications

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“…Additionally, insects that traverse across air/water interfaces need superhydrophobic legs to achieve this feat. Similarly, in atmospheric environments, flying insects need to protect their wings from water, dust, and other pollutants so as not to be overloaded, and in order to preserve their ability to fly [7,8,9,10,11,12,13,14]. When thinking about this myriad of design challenges, the question is, how did these insects manage to control their wettability for these varied environments?…”

Section: Introductionmentioning

confidence: 99%

Variation of Goliathus orientalis (Moser, 1909) Elytra Nanostructurations and Their Impact on Wettability

Godeau

Orange

et al. 2018

Biomimetics

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Abstract:Among the different species of flower beetles, there is one of particular notoriety: the Goliath beetle. This large insect can grow up to 11 cm long and is well-known for its distinctive black and white shield. In this paper, we focus on a particular Goliathus species: G. orientalis (Moser, 1909). We investigated the variations in properties of both the black and white parts of the upper face of G. orientalis; more precisely, the variation in surface properties with respect to the wettability of these two parts. This work reveals that the white parts of the shield have a higher hydrophobic character when compared to the black regions. While the black parts are slightly hydrophobic (θ = 91 ± 5 • ) and relatively smooth, the white parts are highly hydrophobic (θ = 130 ± 3 • ) with strong water adhesion (parahydrophobic); similar to the behavior observed for rose petals. Roughness and morphology analyses revealed significant differences between the two parts, and, hence, may explain the change in wettability. The white surfaces are covered with horizontally aligned nanohairs. Interestingly, vertically aligned microhairs are also present on the white surface. Furthermore, the surfaces of the microhairs are not smooth, they contain nanogrooves that are qualitatively similar to those observed in cactus spines. The nanogrooves may have an extremely important function regarding water harvesting, as they preferentially direct the migration of water droplets; this process could be mimicked in the future to capture and guide a large volume of water.

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Section: Introductionmentioning

confidence: 99%

Variation of Goliathus orientalis (Moser, 1909) Elytra Nanostructurations and Their Impact on Wettability

Godeau

Orange

et al. 2018

Biomimetics

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“…Contact angle data for 5 μL and 2 μL water droplet trials were collected using an experimental setup based on those used previously [37]. The droplet volumes were based on the range of values previously used to test natural materials and fabrics [27,38]. We deposited the water droplet (5 or 2 μL) onto the material piece using a pipette.…”

Section: Plos Onementioning

confidence: 99%

A laboratory-based study examining the properties of silk fabric to evaluate its potential as a protective barrier for personal protective equipment and as a functional material for face coverings during the COVID-19 pandemic

et al. 2020

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The worldwide shortage of single-use N95 respirators and surgical masks due to the COVID-19 pandemic has forced many health care personnel to use their existing equipment for as long as possible. In many cases, workers cover respirators with available masks in an attempt to extend their effectiveness against the virus. Due to low mask supplies, many people instead are using face coverings improvised from common fabrics. Our goal was to determine what fabrics would be most effective in both practices. Under laboratory conditions, we examined the hydrophobicity of fabrics (cotton, polyester, silk), as measured by their resistance to the penetration of small and aerosolized water droplets, an important transmission avenue for the virus causing COVID-19. We also examined the breathability of these fabrics and their ability to maintain hydrophobicity despite undergoing repeated cleaning. Laboratory-based tests were conducted when fabrics were fashioned as an overlaying barrier for respirators and when constructed as face coverings. When used as material in these two situations, silk was more effective at impeding the penetration and absorption of droplets due to its greater hydrophobicity relative to other tested fabrics. We found that silk face coverings repelled droplets in spray tests as well as disposable single-use surgical masks, and silk face coverings have the added advantage over masks such that they can be sterilized for immediate reuse. We show that silk is a hydrophobic barrier to droplets, can be more breathable than other fabrics that trap humidity, and are re-useable via cleaning. We suggest that silk can serve as an effective material for making hydrophobic barriers that protect respirators, and silk can now be tested under clinical conditions to verify its efficacy for this function. Although respirators are still the most appropriate form of protection, silk face coverings possess properties that make them capable of repelling droplets.

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“…Regardless, aquatic insects employ diverse adaptations to circumvent the problem of surface tension in other ways (e.g. [31][32][33][34][35]). Our observations of mosquito larvae and diving beetles, for example, highlight two common themes among air-breathing aquatic insects: the use of narrowdiameter structures to penetrate the surface tension to access air, and the use of hydrophilic and hydrophobic body parts to manipulate the water surface or to trap air bubbles for storage within cuticular hairs [32,33].…”

Section: (B) Lung Emptying and Fillingmentioning

confidence: 99%

Circumventing surface tension: tadpoles suck bubbles to breathe air

Schwenk

Phillips

2020

Proc. R. Soc. B.

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The surface tension of water provides a thin, elastic membrane upon which many tiny animals are adapted to live and move. We show that it may be equally important to the minute animals living beneath it by examining air-breathing mechanics in five species (three families) of anuran (frog) tadpoles. Air-breathing is essential for survival and development in most tadpoles, yet we found that all tadpoles at small body sizes were unable to break through the water's surface to access air. Nevertheless, by 3 days post-hatch and only 3 mm body length, all began to breathe air and fill the lungs. High-speed macrovideography revealed that surface tension was circumvented by a novel behaviour we call ‘bubble-sucking’: mouth attachment to the water's undersurface, the surface drawn into the mouth by suction, a bubble ‘pinched off’ within the mouth, then compressed and forced into the lungs. Growing tadpoles transitioned to air-breathing via typical surface breaching. Salamander larvae and pulmonate snails were also discovered to ‘bubble-suck’, and two insects used other means of circumvention, suggesting that surface tension may have a broader impact on animal phenotypes than hitherto appreciated.

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Wettability gradient on the elytra in the aquatic beetle Cybister chinensis and its role in angular position of the beetle at water-air interface

Cited by 15 publications

References 33 publications

Variation of Goliathus orientalis (Moser, 1909) Elytra Nanostructurations and Their Impact on Wettability

Variation of Goliathus orientalis (Moser, 1909) Elytra Nanostructurations and Their Impact on Wettability

A laboratory-based study examining the properties of silk fabric to evaluate its potential as a protective barrier for personal protective equipment and as a functional material for face coverings during the COVID-19 pandemic

Circumventing surface tension: tadpoles suck bubbles to breathe air

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