Papers by Keyword: Super-Hydrophobic

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Authors: Shu Liang Wang, Chang Yu Liu, Hui Ming Du, Hua Ma, Cheng Xie, Cheng Yu Wang
Abstract: A layer of sword-like super-hydrophobic film was fabricated on wood surface through an alkaline hydrothermal method. The super-hydrophobic property of the wood surface was measured by contact angle measurements (CA). The microstructure and chemical composition of the super-hydrophobic film was analyzed by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR). Analytical characterization revealed that the micro-scale roughness sword-like particles uniformly erect on the wood surface and create the rough surface. Also, a monolayer of stearic acid was adsorbed on the rough surface which contributes to reduce the surface energy. With the combination of roughness and low surface energy of wood surface, the wood has turned its wetting property from hydrophilic into super-hydrophobic with a water contact angle 151o, and the sliding angle is about 5o.
Authors: Liang Ge, Jin Yuan Yao, Hong Wang, Gui Fu Ding
Abstract: In this paper, we prepared an octadecyltrichlorosilane(OTS) super-hydrophobic film using phase separation method to demonstrate the anti-icing property of super-hydrophobic surfaces. We investigated the super-hydrophobicity of the surface in -5°C environment, as well as the icing process of water droplets on the surface which proceeded at the temperature low to -15°C. We found that the prepared OTS film retained its super-hydrophobicity in the -5°C environment by the measurement of contact angle. It was observed that the icing progress of water droplets on the super-hydrophobic surface was greatly retarded. Based on the classical heterogeneous nucleation theory, it concluded that the ice formation is directly related to the surface wettability. This research would be beneficial to the preparation of anti-icing films.
Authors: Ping Wang, Yan Sheng Yin, Tao Liu
Abstract: Self-assembled monolayer of n-tetradecanoic acid (CH3(CH2)14COOH) are formed on the native oxide surfaces of Fe3Al. The structure of the monolayer is probed with contact angle measurement and SEM. The results (indicate) that the structure of the adsorbed film like lotus structure and the contact angle are larger than 150° for seawater. Moreover, the corrosion behavior of bare Fe3Al and Fe3Al with super-hydrophobic surface, with two different surface microstructure, in seawater(pH=8.02), has been investigated using electrochemical impedance spectroscopy (EIS) and weight loss measurements. Both methods reveal that corrosion rate of Fe3Al with Super-hydrophobic surface sample decreases dramatically because of its special microstructure. These results indicate that the super-hydrophobic surface formed on the Fe3Al can improve corrosion resistance of Fe3Al in seawater significantly.
Authors: Dong Ki Lee, Jun Hyung Lee, Young Hak Cho
Abstract: This paper shows how much the size of groove and ridge, which were fabricated on the silicon wafer, affected on the hydrophobicity of the grooved surface without chemical treatments and with chemical treatment such as self-assembled monolayers (SAMs) of organic silane. Furthermore, the contact angles (CAs) of water droplet on specimens were measured and compared with theoretical CAs of droplet in Cassie-Baxter state. The experimental results indicated that the specimen with the extensive groove width had super-hydrophobicity as compared to the specimen with relatively narrow groove width. The highest CAs of chemically non-treated specimens and chemically treated specimens were 171.9˚ and 173.1˚. This work explains that the grooved surface with nano-ridges and SAM coating contributes to improve hydrophobicity of surface.
Authors: Yan Ling Wan, Zhong Xu Lian, Hua Dong Yu, Jin Kai Xu
Abstract: We present a method to fabricate superhydrophobic surfaces on copper substrate using reciprocating type high speed wire cut electrical discharge machining (HS-WEDM) and self-assembly technology. Herein, single factor experiment was used to investigate the influence of several major parameters of the wire electrical discharge machining processing, such as pulse width, pulse gap (pulse interval) and power tube, on the contact angle of resulting surface. Results show that a composite structure, composed of craters and projections, is fabricated on the copper surface, which is the key reason of superhydrophobicity. With the change of pulse width, pulse interval, and the number of the power tube, the hydrophobic properties of resulting copper surface was changed. This paper provided the theoretical support for industrialized fabrications of super-hydrophobic brass surface.
Authors: Chun Mao Kang, Jin Yan Ji, Jun Li Zhao, Hong Peng Zhong, Jiao He, Yu Ma, Mu Huo Yu
Abstract: Facile fabrication of bio-mimic super-hydrophobic surfaces has attracted attentions in both fundamental research and practical application. In this article, we developed a simple one step etching method to fabricate a super-hydrophobic surface on aluminum surface. The contact angel of water reaches 155.9° without coating any low energy materials. Surface morphology clearly demonstrates a combination of micro/nanohierarchical structures. Moreover, such surface remarkably shortens the bursting time of air bubbles under water. For a middle size bubble about 1mm, the bursting time at super-hydrophobic surface shortens to about 20%, comparing to freely bursting. This intriguing effect may contribute to future expand applications of super-hydrophobic surface in industrial field, such as fiber spinning.
Authors: Zhan Ping Zhang, Yu Hong Qi, Yan Zhang, Gui Ke Mo, Jing Zhao Wang
Abstract: A hierarchical roughness surface with micro-and nano-structures was fabricated on mild steel by chemical etching with a mixture acid (2%HNO3 + 6%H2SO4 + 6%H3PO3) solution. The surface was modified by fluoroalkylsilane. The wettability of the modified surfaces was studied by contact angle method and Electrochemical Impedance Spectroscopy (EIS), and their morphology was investigated by Scanning Electron Microscopy (SEM). The roughness of the steel etched consisted of fine micro-steps in grains. The treated surface exhibited super-hydrophobic properties, water contact angle is high to 152° after modification for 6 min at room temperature. The results indicated that with the increase of etching time, the hierarchical structure gradually formed on the surface and the contact angle gradually decreased.
Authors: Hong Tao, So King Ho, Echo Li, Xue Zhu Zhang, Gary Lai
Abstract: Chemically and mechanically protective coatings are formed on surface of Magnesium alloys by micro-arc oxidation (MAO) methods. Modification of the obtained MAO surfaces was made in two aspects. Firstly, the protection is enhanced by forming super-hydrophobic surfaces, with water contact angle higher than 120o, attributed to hierarchical nanomicro structures. The overall process involves alkaline etching to form nanoscale structures on top of micro-porous surface achieved during micro-arc oxidation processes. Secondly, the electrical property of the MAO surfaces is modified. A film with electrical conductivity of 2.4Ω/sq is achieved by Ni deposition and characterized by four point probe measurement. The morphology, phase, and chemical composition of all surfaces are investigated by SEM, AFM, and XRD analysis.
Authors: Yuan Yuan Chen, Jin Gou Ji, Ting Lu
Abstract: The super-hydrophobic coating with self-cleaning property was prepared by particle-filling method based on nanometer SiO2 (n-SiO2) and TiO2 (n-TiO2) as filler. The surface properties of the coating were tested by contact angle (CA) goniometer and atomic force microscopy (AFM). The results indicate that the contact angle (CA) of the coating is above 160°. The surface of the coating possesses a natural lotus-like micro-and nanohierarchical structure. The CA is recovered gradually from 85° to 138° with procedure the photocatalytic degradation of the oil pollutant for 7 hours. The adhesive force between the coating and icing decreases about 80% compared with that of bare glass surface and icing.
Authors: Peng Wang, Dun Zhang, Peng Ju
Abstract: Copper film with rough structure is prepared on metal surface via electro-deposition. After modification of tetradecanoic acid, copper film presents super-hydrophobic property with water contact angle of 151.1°, which could be attributed to the rough structure by trapping air. The adhesion test shows that the modified copper surface has low apparent water adhesion to the suspending droplet. Electrochemical measurement proves that super-hydrophobic film can inhibit corrosion of copper effectively. The method proposed in this paper is time-saving and facile to operate, and it offers a promising technique to prepare metallic surface with super-hydrophobic property.
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