The Experts below are selected from a list of 37653 Experts worldwide ranked by ideXlab platform
Tsutomu Minami - One of the best experts on this subject based on the ideXlab platform.
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Superhydrophobic - Superhydrophilic micropatterning on flowerlike alumina coating film by the sol - Gel method
Chemistry of Materials, 2000Co-Authors: Kiyoharu Tadanaga, J. Morinaga, A Matsuda, Tsutomu MinamiAbstract:A novel route to form Superhydrophobic−superhydrophilic micropatterned coating film has been developed. UV light was irradiated on the Superhydrophobic coating film which consists of three layers, a flowerlike Al2O3 gel film, a very thin TiO2 gel layer, and a FAS layer, to cleave the fluoroalkyl chain in FAS selectively, and well-defined Superhydrophobic and superhydrophilic regions were formed.
Jianfu Ding - One of the best experts on this subject based on the ideXlab platform.
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verification of icephobic anti icing properties of a Superhydrophobic surface
ACS Applied Materials & Interfaces, 2013Co-Authors: Yuanyi Wang, Qingmin Chen, Qingjun Wang, Jianfu DingAbstract:Four aluminum surfaces with wettability varied from superhydrophilic to Superhydrophobic were prepared by combining an etching and a coating process. The surface wettability was checked in terms of water contact angle (CA) and sliding angle (SA) under different humidity at −10 °C. High-speed photography was applied to study water droplet impact dynamics on these surfaces. It was found that single and successive water droplets could rebound on the Superhydrophobic surface and roll off at a tilt angle larger than 30° under an extremely condensing weather condition (−10 °C and relative humidity of 85–90%). In addition, the Superhydrophobic surface showed a strong icephobic property, the ice adhesion on this surface was only 13% of that on the superhydrophilic surface, though they had a similar nano/microtopological structure. Moreover, this Superhydrophobic surface displayed an excellent durability of the icephobic property. The ice adhesion only increased to 20% and 16% of that on the Superhydrophobic surfa...
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Verification of icephobic/anti-icing properties of a Superhydrophobic surface
ACS Applied Materials and Interfaces, 2013Co-Authors: Yuanyi Wang, Jian Xue, Qingmin Chen, Qingjun Wang, Jianfu DingAbstract:Four aluminum surfaces with wettability varied from superhydrophilic to Superhydrophobic were prepared by combining an etching and a coating process. The surface wettability was checked in terms of water contact angle (CA) and sliding angle (SA) under different humidity at -10 °C. High-speed photography was applied to study water droplet impact dynamics on these surfaces. It was found that single and successive water droplets could rebound on the Superhydrophobic surface and roll off at a tilt angle larger than 30° under an extremely condensing weather condition (-10 °C and relative humidity of 85-90%). In addition, the Superhydrophobic surface showed a strong icephobic property, the ice adhesion on this surface was only 13% of that on the superhydrophilic surface, though they had a similar nano/microtopological structure. Moreover, this Superhydrophobic surface displayed an excellent durability of the icephobic property. The ice adhesion only increased to 20% and 16% of that on the Superhydrophobic surface after the surface was undergone 20 icing/ice-breaking cycles and 40 icing/ice-melting cycles, respectively. Surface profile and XPS studies on these surfaces indicated a minor damage of the surface nano/microstructure and the coating layer upon these multiple ice-breaking and ice-melting processes. Therefore, this Superhydrophobic surface could be a good candidate for icephobic applications.
Ching-ping Wong - One of the best experts on this subject based on the ideXlab platform.
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UV and thermally stable Superhydrophobic coatings from sol-gel processing
Journal of Colloid and Interface Science, 2008Co-Authors: Yonghao Xiu, Dennis W. Hess, Ching-ping WongAbstract:A method for the preparation of inorganic Superhydrophobic silica coatings using sol-gel processing with tetramethoxysilane and isobutyltrimethoxysilane as precursors is described. Incorporation of isobutyltrimethoxysilane into silica layers resulted in the existence of hydrophobic isobutyl surface groups, thereby generating surface hydrophobicity. When combined with the surface roughness that resulted from sol-gel processing, a Superhydrophobic surface was achieved. This surface showed improved UV and thermal stability compared to Superhydrophobic surfaces generated from polybutadiene by plasma etching. Under prolonged UV tests (ASTM D 4329), these surfaces gradually lost Superhydrophobic character. However, when the as-prepared Superhydrophobic surface was treated at 500 °C to remove the organic moieties and covered with a fluoroalkyl layer by a perfluorooctylsilane treatment, the surface regained Superhydrophobicity. The UV and thermal stability of these surfaces was maintained upon exposure to temperatures up to 400 °C and UV testing times of 5500 h. Contact angles remained >160° with contact angle hysteresis ∼2°. © 2008 Elsevier Inc. All rights reserved.
Masoud Farzaneh - One of the best experts on this subject based on the ideXlab platform.
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Durable icephobic coatings
16e Colloque annuel de la CIGELE, 2014Co-Authors: Reza Jafari, Masoud FarzanehAbstract:Here, our recent advances in applications of various technologies in development of Superhydrophobic and icephobic surfaces have been presented. Plasma polymerization technology which is one of the common treatment technologies, was used to create the Superhydrophobic and icephobic coating. This process is relatively fast, economical and results in stable coatings with a high degree of controllability. By using a plasma polymerisation of hexamethyldisiloxane (HMDSO) in the inductively coupled RF (13.56 MHz) plasma reactor (HICP-600SB, Plasmionique Inc.) aSuperhydrophobic coating with a high static contact angle about 160 º was obtained. Furthermore, the Superhydrophobic coating can reduce the ice adhesion strength of an aluminum surface 11.6 times. The durability of plasma polymerized coatings was studied under extreme environmental conditions such as UV degradation, immersion in different pH solutions and after several icing/de-icing cycles. By sputtering of polytetrafluoroethylene (PTFE or Teflon) on an anodized aluminium surface, an icephobic and Superhydrophobic coating was prepared. This Teflon-like coatings exhibited a high static contact angle of ~ 165º with a very low contact angle hysteresis of ~ 3º and showed an ice adhesion strength reduction of 3.5 times. However, these coatings showed a decrease in stability after several icing/de-icing cycles. In order to improve their durability of the Teflon-like coating, the input power of the discharge was increased during the sputtering process. Low variations in ice adhesion strength were observed after as many as 9 icing/de-icing cycles
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On Hydrophobic and Icephobic Properties of TiO2-Doped Silicon Rubber Coatings
International Journal of Theoretical and Applied Nanotechnology, 2012Co-Authors: Faranak Arianpour, Masoud FarzanehAbstract:In the present work, flat and micro-/nano-rough water and ice-repellent coatings based on room-temperature vulcanized silicone rubber (RTV SR) incorporated with titania (TiO2) nanopowder as a dopant were prepared and investigated. Such water and ice-repellent coatings are potential candidates for protecting high-voltage equipment such as conductors and insulators. Supehydrophobic samples with contact angle (CA) >145o and contact angle hysteresis (CAH) ~5-10o were prepared by spin coating TiO2-loaded RTV SR suspensions on etched substrates. The SEM investigations of the sample surfaces revealed that the alumina filler (loaded into the as-supplied silicone rubber product) had some influence on the surface topographies of the prepared coatings. It was also found that the nanopowders used as dopants further increased the surface roughness (and correspondingly - water repellency) of the coatings. While the TiO2-doped RTV SR demonstrates high CA and low CAH values, which is characteristic of the Cassie wetting regime, the wetting mode on the rough RTV SR coated sample with high CAH is expected to be a mixed Cassie-Wenzel regime. The anti-icing behaviour of the coating was studied under atmospheric icing conditions. Rough Superhydrophobic coatings prepared with TiO2 nanoparticles of dielectric constant (~80) resulted in reducing the ice adhesion strength by at least ~7 times compared to a mirror-polished aluminium sample and by ~9 times compared to an as-received aluminium sample. At approximately -15 oC, water droplets were found to freeze on polished aluminium after approximately 5 s, while their freezing was delayed by as long as ~12-13 min on a Superhydrophobic nanocomposite surface doped with TiO2 powder. This delay is explained by the insulating properties of the rough surface that entraps a significant amount of air into its structure. Therefore, the coatings prepared show promise for industrial applications on high-voltage equipment, including insulators, since they can reduce ice accumulation, while also reducing the risk of flashover on outdoor insulators.
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Nanostructured Superhydrophobic Coatings
Journal of CPRI, 2008Co-Authors: Masoud Farzaneh, D K SarkarAbstract:A short description of the activities and facilities of the CIGELE/INGIVRE Chairs in relation with Superhydrophobic and icephobic nanometric coatings has been reported. A brief description of how Superhydrophobicity can help mitigate the ice accretion problem on power network equipment and other exposed structures by reducing adhesion of ice to surface has been presented. Basic models namely the Wenzel and Cassie-Baxter models accounting for the contact angle of water on solid surfaces relating to the influence of surface roughness on hydrophobicity have been discussed. The CIGELE/INGIVRE research team involved in the development of nanometric materials is actively working on the elaboration of Superhydrophobic aluminium surfaces by chemical etching, Superhydrophobic copper surfaces by silver nanoparticles, Superhydrophobic nanostructured oxides and Superhydrophobic nanofibres. Some of the promising results achieved on Superhydrophobicity have been described.
Woonbong Hwang - One of the best experts on this subject based on the ideXlab platform.
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Anti-frosting on Superhydrophobic Surface
Lecture Notes in Electrical Engineering, 2019Co-Authors: Hyundo Hwang, Jongseon Choi, Woonbong HwangAbstract:The Superhydrophobic surface can be used in a various fields due to the special wetting behavior. In this paper, distinct characteristics of the Superhydrophobic aluminum surface fabricated by simple dipping methods are reported. The Superhydrophobicity on the aluminum surface can be realized by hierarchical structures by chemical etching and alkali treatment process, and by low surface energy treatment by a self-assembled monolayer coating using hydrophobic material. As a result, the Superhydrophobic aluminum has a high contact angle of 162° and a low hysteresis angle of 2.9°. The fabricated Superhydrophobic aluminum surface has a great mechanical durability, so that the surface is improved surface modulus and hardness. In addition, frost is hardly adhered onto the surface due to the Superhydrophobicity. The large-area Superhydrophobic surface can be fabricated owing to the simple fabrication method using dipping methods, so that the Superhydrophobic heat exchanger is fabricated which have excellent anti-wetting property. These advantages demonstrated in this paper will enhance the applicability to a variety of industrial fields such as home appliances and electrical appliances.
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simple fabrication method of flexible and translucent high aspect ratio Superhydrophobic polymer tube using a repeatable replication and nondestructive detachment process
Chemical Engineering Journal, 2019Co-Authors: Woonbong HwangAbstract:Abstract Superhydrophobic tubes with excellent liquid transfer capability due to the drag reduction property have attracted considerable attention in recent years. However, there are several challenges in the fabrication of Superhydrophobic tubes using previously reported methods. Herein, a simple method to fabricate Superhydrophobic polydimethylsiloxane (PDMS) tube via a replication and detachment process using a Superhydrophobic mold is reported. The fabricated tube is translucent and highly flexible owing to the good optical and mechanical properties of PDMS. The translucent and flexible tube with a high aspect ratio exhibited excellent Superhydrophobicity without the need for additional chemical treatments. Significantly, the polymer replica can be separated spontaneously without damaging the mold, because of the nondestructive detachment process using swelling effect of PDMS. Thus, the replication can be repeated for fabricating Superhydrophobic tubes using a single mold. Owing to the superior anti-wetting property, liquids can be transported better through the fabricated Superhydrophobic tube than a normal tube. In addition, blood can be delivered without contaminating the tube. These distinct characteristics will extend the applicability of Superhydrophobic tubes to various fields requiring productivity as well as optical and mechanical advantages, such as medical devices.
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repeatable replication method with liquid infiltration to fabricate robust flexible and transparent anti reflective Superhydrophobic polymer films on a large scale
Chemical Engineering Journal, 2018Co-Authors: Hee Jae Hwang, Dukhyun Choi, Woonbong HwangAbstract:Abstract Flexible Superhydrophobic films that can be adapted to any target object for practical applications have drawn much attention in recent years. In this paper, we propose a simple method to fabricating highly flexible Superhydrophobic polydimethylsiloxane (PDMS) films, via a repeatable replication and nondestructive detachment from a Superhydrophobic aluminum mold. Due to the hierarchical surface structures and intrinsic hydrophobicity of PDMS, the fabricated films exhibited superior water repellency without any further modifications using low surface energy materials. Moreover, these water repellent films exhibited excellent mechanical durability and flexibility without losing the anti-wetting property under harsh conditions. The use of a robust Superhydrophobic mold and the easy detachment of the film using a solution with a low surface tension allow for the clean release of large-area replicas without any damages to the mold. This enables the repeated fabrication of Superhydrophobic PDMS films without the deterioration of their wettability using a single mold. Furthermore, the Superhydrophobic PDMS film exhibited an efficient anti-reflection property and high transparency, which allows an enhanced light collection and efficiency when applied to solar cells. Consequently, this simple and inexpensive method is appropriate for diverse applications that require films with superior mechanical and optical properties, and a special wetting behavior.
