Superhydrophobic Self-cleaning Surfaces in Nature

Mohammed S., Selim

doi:10.37256/nat.112020121.26-37

Cited by 10 publications

(4 citation statements)

References 68 publications

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“…Nature has always inspired mankind through billions of years of evolution. Various surfaces found in nature are superhydrophobic, such as butterfly wings, ,, water strider legs, , and canna and taro leaves . Pauli, the Nobel Prize winner in physics in 1945, said, ″God made solids, but surfaces were the work of the devil.″ These superhydrophobic, low-adhesion surfaces exhibit self-cleaning properties by allowing water to roll off easily and freely.…”

Section: Methodsmentioning

confidence: 99%

Biomimetic Multiwalled Carbon Nanotube/Polydimethylsiloxane Nanocomposites with Temperature-Controlled, Hydrophobic, and Icephobic Properties

Sun

Wang

Sui

et al. 2021

ACS Appl. Nano Mater.

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Retarding and preventing ice/frost formation have increasing importance in aerospace applications because of widespread energy and safety concerns. In this study, multiwalled carbon nanotube−polydimethylsiloxane (MWCNT/PDMS) nanocomposites were fabricated via mechanical stirring and three-roll grinding. By imitating the microstructures of lotus leaves, various biomimetic nanocomposites were prepared by etching micropillar arrays on MWCNT/PDMS nanocomposites. These biomimetic nanocomposites possess superior flexibility, electrical conductivity, hydrophobicity, and icephobicity. Effects of the micropillar height on the wettability, freezing process of water droplets, ice/frost formation, and ice adhesion strength were characterized; influences of temperature on the wettability and strength of ice adhesion and feasibility of electrothermal deicing were investigated. The surface wettability, freezing process of water droplets, ice/frost formation, and ice adhesion strength in the Cassie state are independent of the micropillar height. However, compared to flat surfaces, the adhesion strength of ice increases, and formation of ice/frost decreases because of the presence of surface micropillars. At the same micropillar height, an increase in temperature decreases the contact angle and ice adhesion strength. The results indicate that the surface microstructure designability and flexible temperature-controllability of biomimetic nanocomposites have great potential for use in aerospace (anti-/deicing) applications.

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Section: Methodsmentioning

confidence: 99%

Biomimetic Multiwalled Carbon Nanotube/Polydimethylsiloxane Nanocomposites with Temperature-Controlled, Hydrophobic, and Icephobic Properties

Sun

Wang

Sui

et al. 2021

ACS Appl. Nano Mater.

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“…Kemampuan superhidrofobik yang dimiliki lebih stabil dibandingkan dengan tanaman lain ditunjukkan dengan nilai sudut kontak air sebesar 160°. Selain nilai sudut kontak air, adapun beberapa faktor yang menjadi pendukung dalam kemampuan superhidrofobiknya diantaranya, bentuk mikrostruktur epidermis, kristal lilin epikutikular nanoskopik dari daun, dan stabilitas superhidrofobik di bawah kondisi kondensasi lembab (Mohammed S., 2020). Sifat superhidrofobik daun Teratai dalam kemampuan self-cleaning disebut sebagai "Lotus effect" dimana sebutan ini digunakan untuk menggambarkan sifat permukaan analog yang ditunjukkan oleh bahan sintetis.…”

Section: Daun Lotusunclassified

“…Sayap kupu-kupu memiliki permukaan kasar sehingga dapat bersifat hidrofobik dan dapat meningkatkan kemampuan self-cleaning, selain itu memiliki arah adhesi radial keluar ditunjukkan pada SEM sayap kupu-kupu pada Gambar 2(b) (Mohammed S., 2020). Kemampuan self-cleaning yang dimiliki karena permukaannya anisotropik yang menyebabkan sayapnya bebas kotoran secara alami.…”

Section: Sayap Kupu-kupuunclassified

Review: Lapisan Superhidrofobik Berbasis Silika Sebagai Aplikasi Self-Cleaning

Putri,

MUNASIR

2023

Inov. Fis. Indones.

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Teknologi self-cleaning sangat popular di kalangan para peneliti dan telah banyak diterapkan dalam berbagai aplikasi permukaan. Lapisan self-cleaning dengan sifat superhidrofobik banyak dikembangkan dan diteliti lebih lanjut karena kemampuannya dalam melakukan pembersihan yang sangat baik. Kemampuan self-cleaning lapisan superhidrofobik berbasis silika (SiO2) banyak diteliti. SiO2 dianggap dapat meningkatkan kekasaran suatu permukaan karena memiliki energi permukaaannya yang rendah dan menunjukkan sifat hidrofobik, hidrofilik, dan kestabilan termal. Lapisan superhidrofobik berbasis silika telah disintesis melalui berbagai metode fisik dan kimia. Metode sol-gel menjadi utama dengan ciri khas kemudahannya dalam sintesis melalui pencampuran beberapa material dan lebih hemat biaya. Selain itu, metode sol-gel telah banyak digunakan dalam sintesis material berbasis silika. Pada review ini, membahas mengenai fenomena self-cleaning di alam yang menjadi acuan peneliti, karakteristik lapisan superhidrofobik dalam kemampuan self-cleaning, metode sol-gel dan teknik coating dalam pembuatan lapisan superhidrofobik, dan material silika yang dimodifikasi dengan material lain untuk meningkatkan kemampuan self-cleaning. Kata Kunci: Superhidrofobik; Self-cleaning; Silika; Sol-gel Abstract Self-cleaning technology is very popular among researchers and has been widely applied in various surface applications. Self-cleaning coatings with superhydrophobic properties have been developed and further researched because of their ability to perform excellent cleaning. The self-cleaning ability of silica-based superhydrophobic coatings (SiO2) has been extensively studied. SiO2 considered to be able to increase the roughness of a surface because it has a low surface energy and exhibits hydrophobic, hydrophilic, and thermal stability properties. Silica-based superhydrophobic coatings have been synthesized by various physical and chemical methods. The sol-gel method is the main feature of its ease of synthesis through mixing several materials and is more cost-effective. In addition, the sol-gel method has been widely used in the synthesis of silica-based materials. This review discusses the phenomenon of self-cleaning in nature which is the reference for researchers, the characteristics of the superhydrophobic coating in terms of self-cleaning ability, the sol-gel method and coating techniques in the manufacture of superhydrophobic coatings, and silica material modified with other materials to increase self-cleaning ability. Keywords: Superhydrophobicity; Self-cleaning; Silica; Sol-gel

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“…Oil-infused surfaces have been demonstrated to withstand drop impact pressures of up to 680 atm . Textured oil-impregnated surfaces are also self-cleaning − and omniphobic; that is, they repel a variety of fluids including low-surface-tension liquids (e.g., hexane and other organic liquids) and complex liquids (e.g., blood). , Although past studies have demonstrated the potential of lubricant-impregnated surfaces for enhancing various applications, including biofouling prevention, , drag reduction, , and increased heat transfer rate in condensation , and water harvesting, , currently these surfaces are not used in real-world applications due to the concern of shear-induced oil depletion. − …”

mentioning

confidence: 99%

Visualization and Experimental Characterization of Wrapping Layer Using Planar Laser-Induced Fluorescence

Xu,

Herzog,

Zhou

et al. 2024

ACS Nano

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Droplets on nanotextured oil-impregnated surfaces have high mobility due to record-low contact angle hysteresis (∼1−3°), attributed to the absence of solid−liquid contact. Past studies have utilized the ultralow droplet adhesion on these surfaces to improve condensation, reduce hydrodynamic drag, and inhibit biofouling. Despite their promising utility, oil-impregnated surfaces are not fully embraced by industry because of the concern for lubricant depletion, the source of which has not been adequately studied. Here, we use planar laser-induced fluorescence (PLIF) to not only visualize the oil layer encapsulating the droplet (aka wrapping layer) but also measure its thickness since the wrapping layer contributes to lubricant depletion. Our PLIF visualization and experiments show that (a) due to the imbalance of interfacial forces at the three-phase contact line, silicone oil forms a wrapping layer on the outer surface of water droplets, (b) the thickness of the wrapping layer is nonuniform both in space and time, and (c) the time-average thickness of the wrapping layer is ∼50 ± 10 nm, a result that compares favorably with our scaling analysis (∼50 nm), which balances the curvature-induced capillary force with the intermolecular van der Waals forces. Our experiments show that, unlike silicone oil, mineral oil does not form a wrapping layer, an observation that can be exploited to mitigate oil depletion of nanotextured oil-impregnated surfaces. Besides advancing our mechanistic understanding of the wrapping oil layer dynamics, the insights gained from this work can be used to quantify the lubricant depletion rate by pendant droplets in dropwise condensation and water harvesting.

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Superhydrophobic Self-cleaning Surfaces in Nature

Cited by 10 publications

References 68 publications

Biomimetic Multiwalled Carbon Nanotube/Polydimethylsiloxane Nanocomposites with Temperature-Controlled, Hydrophobic, and Icephobic Properties

Biomimetic Multiwalled Carbon Nanotube/Polydimethylsiloxane Nanocomposites with Temperature-Controlled, Hydrophobic, and Icephobic Properties

Review: Lapisan Superhidrofobik Berbasis Silika Sebagai Aplikasi Self-Cleaning

Visualization and Experimental Characterization of Wrapping Layer Using Planar Laser-Induced Fluorescence

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