抗结冰涂层: 从表面化学到功能化表面

在交通运输、航空航天、电力通信等诸多领域,结冰给人类和社会带来很大危害和安全隐患。现有的抗结冰方法如机械除冰、加热除冰以及喷洒化学试剂等虽然有效,但是存在耗能大和环境污染等问题。在基体表面涂装具有抗结冰性能的功能涂层被认为是一种必要的切实有效的方法,近年来备受关注。本文在介绍了涂层抗结冰原理及基体表面结冰影响因素的基础上,详细综述了近年来各类抗结冰涂层取得的研究成果,主要包括牺牲性涂层、疏冰涂层和超疏水涂层。重点介绍了制备抗结冰涂层所用的材料及方法,并分析了各种抗结冰涂层的优缺点,指出了抗结冰涂层目前存在的问题,最后对抗结冰涂层的发展趋势进行了分析和展望。     

UV and thermally stable polystyrene‐MWCNT superhydrophobic coatings

A facile method for ultraviolet (UV) and thermally stable polystyrene‐multiwalled carbon nanotubes (PS‐MWCNT) superhydrophobic coatings was demonstrated by a simple spray coating method. The superhydrophobicity was understood by an increase in micro/nano roughness with the addition of MWCNTs. Surface morphology of the coatings showed protrusion like structure. The wetting behavior of the coatings was studied as a function of temperature, and it is observed that the coatings were superhydrophobically stable up to 250 °C. A transformation of superhydrophobic to superhydrophilic state is achieved at 300 °C. The coatings remained superhydrophobically stable when it was subjected to UV‐irradiation and water immersion of 50 h. Thermogravimetric analysis showed a small shift (10°) towards higher temperature region with an addition of MWCNTs, suggesting the presence of weak interactions between PS and MWCNT, which is also supported by Fourier transform infrared spectroscopy, Raman and X‐ray photoelectron spectroscopy studies. Both hydrophilic and superhydrophobic coatings find potential applications in our daily life. Copyright © 2016 John Wiley & Sons, Ltd.     

Superhydrophobic PTFE Surfaces by Extension

Summary: A rather simple but yet effective way to achieve a superhydrophobic film by extending a Teflon film is proposed. The water‐contact angle can be increased from 118 to 165° by extending to ca. 190%. The fibrous crystals and the increasing distance between the fibrous crystals are believed responsible for the high water‐contact angle. It indicates that the density of the aligned microstructures is very important for the superhydrophobicity.

Water‐contact angle and the corresponding shapes of water droplets as a function of extension ratio of Teflon tape.     

复合SiO2粒子涂膜表面结构及超疏水性能

采用溶胶-凝胶法制备不同粒径SiO₂粒子，通过表面改性得到不同形状复合粒子，并利用氟硅氧烷的表面自组装功能制备了具有“荷叶效应”的超疏水涂膜。通过原子力显微镜、扫描电镜和水接触角的测试对膜结构及性能进行了表征，探讨了SiO₂粒子的粒径和形状与表面微观结构、表面粗糙度和表面疏水性能的关系。结果表明含单一粒径粒子涂膜表面水接触角符合Wenzel模型，而复合粒子构成了符合Cassie模型的非均相界面;单纯的粗糙度因子不能反映水接触角的变化，复合粒子在膜表面的无规则排列赋予涂膜表面不同等级的粗糙度，使得水滴与涂膜表面接触时能够形成高的空气捕捉率和较小的粗糙度因子;其与在涂膜表面能形成自组装分子膜的氟硅氧烷共同作用赋予了涂膜超疏水性能，而这种超疏水性能与复合粒子的粒径大小和形状基本无关。     

花生叶表面的高黏附超疏水特性研究及其仿生制备

花生是一种常见的豆科作物.与低黏附超疏水的荷叶不同,花生叶表面同时具有超疏水和高黏附特性.水滴在花生叶表面的接触角为151±2°,显示出超疏水特性.此外,水滴可以牢固地附着在花生叶表面,将花生叶翻转90°甚至180°,水滴均不会从表面滚落,显示了良好的黏附性(黏附力超过80μN).研究发现,花生叶表面呈现微纳米多级结构,丘陵状微米结构表面具有无规则排列的纳米结构.花生叶表面特殊的微纳米多尺度结构是其表面呈现高黏附超疏水特性的关键因素.结合实验数据,对花生叶表面特殊浸润性机理进行了简要阐述.受此启发,利用聚二甲基硅氧烷复形得到了与花生叶表面微结构类似的高黏附疏水表面.本文以期为仿生制备高黏附超疏水表面提供新思路.     

两步法制备超疏水性ZnO纳米棒薄膜

采用两步法制备了超疏水性ZnO纳米棒薄膜,在用磁控溅射在普通玻璃衬底上生长一层ZnO籽晶层基础上,利用液相法制备了空间取向高度一致的ZnO纳米棒阵列,经修饰后由亲水性转变为超疏水性.用扫描电子显微镜观察了纳米棒的表面结构,用接触角测量仪测出水滴在ZnO纳米棒薄膜表面的接触角为151°±05°,滚动角为7°.用Cassie模型对ZnO纳米棒薄膜的超疏水性进行了验证. 关键词： ZnO纳米棒 超疏水 两步法     

Spray-Coated Metal Hexadecanoate-Based Coatings with Robust Superhydrophobicity and Repairability

With the aim of creating a new avenue for the real applications of the superhydrophobic surface, we succeeded in fabricating metal hexadecanoate (e.g., zinc hexadecanoate) based superhydrophobic coatings on virtually any substrates by the simple spray-coating. Hierarchical rough surface morphology was achieved on the coating with the contact angle of about 160° and the sliding angle of about 6°. The advantages of the present approach include the cheap raw materials, environmentally benign solvents, an industrial implementation method, and easy repairability and applicability so as to make a great application potential in practice. Water repellency of the fabricated coating was demonstrated by visible experiment results and contact angle measurements. The robustness and repairability of the superhydrophobic coating were also investigated by the designed experiments.     

pH‐ and Voltage‐Switchable Superhydrophobic Surfaces by Electro‐Copolymerization of EDOT Derivatives Containing Carboxylic Acids and Long Alkyl Chains

In order to produce pH‐ and voltage‐switchable superhydrophobic surfaces, PEDOT derivatives containing various proportions of a EDOT monomer containing carboxylic groups (EDOT? COOH) and EDOT monomer‐containing dodecyl chains (EDOT? O? H₁₂) are elaborated. The surface morphology and roughness depend highly on the proportion of the monomers. Superhydrophobic properties are reached for a mol % of EDOT? COOH between 0 and 25 %. It is possible to switch from superhydrophobic to hydrophilic (θ_water until about 45°) by electrochemical reduction at low voltage (?1 V vs SCE) to remove the doping anions, following by treatment with NaOH to change the carboxylic groups into carboxylate. By elaborating smooth surfaces of each polymer, the effect of each treatment is reported. The reversibility of the reactions is also reported.     

Robust Nonsticky Superhydrophobicity by the Tapering of Aligned ZnO Nanorods

The robust nonsticky superhydrophobicity of aligned nanoneedle films is reported. A facile, efficient, cheap, and available method based on the diffusion‐limited crystal growth principle is proposed for controlling the tapering of ZnO nanorods, the profiles of which can be tuned effectively by synergetic control over reaction time and temperature in an extremely strong alkaline reaction system. The synthesized nanoneedle, nanopencil, and nanorod arrays are chosen for studying the effects of nanoscale topography on anti‐droplet‐sticking ability. After silanization, all of them show excellent quasi‐static anti‐droplet‐stickiness, and water adhesion along the normal and lateral directions can be greatly reduced by the tapering of nanorods and eliminated by sharp nanoneedles. However, their antisticking stability is distinct under the droplet impact: the nanoneedle sample is still nonsticky but the nanorod sample loses its antisticking ability. Only ensuring the liquid/air interface is in the suspended nonwetting state is insufficient to obtain robust nonsticky surfaces, which also require extremely low solid–liquid van der Waals attraction.     

荷叶效应的研究

荷叶效应源于物体表面微米-纳米结构带来的超疏水性本文通过较为简便的实验装置,研究了超疏水表面的水滴形态;在MATLAB环境下,利用图形工具箱(IPT)对数字图像进行处理;结台Runge-Kutta算法和Newton-Raphson迭代法,通过拟台Young-Laplace方程实现了对接触角较高精度的测量;并在此基础上,...