超疏水涂层表面粗糙结构对防覆冰性能的影响

结冰给交通、电力输送和航空等领域带来极大的安全隐患,研究防覆冰技术具有重要的应用价值。目前最具前景的防冰方法是涂层防冰,本文介绍了疏水涂层的构建方法,阐述了涂层疏水性和疏冰性之间的关系;重点论证了涂层表面粗糙结构对其防覆冰性能的影响,指出防覆冰涂层研发中存在的问题,并对该领域的发展趋势进行了分析和展望。     

超疏水性表面的制备及应用进展

近年来,受荷叶、水黾腿、壁虎脚等天然超疏水生物表面特性的启发,研究者们进行了大量仿生超疏水表面材料的制备及应用研究。超疏水性表面因其特殊的微纳分层结构,具有自清洁、防覆冰、防腐蚀、减阻等优异性能。本文阐述了表面润湿、疏水的基本机理,以及超疏水表面研究的理论基础,对超疏水表面制备的最新研究进展进行了综述,并揭示了研究中存在的问题。最后,介绍了超疏水表面在涂料、织物、防腐、抗菌及防雾等领域中的应用,展望了其未来的研究方向和前景。     

防覆冰涂层构建机理及制备

航空、通信、电力和运输设备的覆冰现象给人们的生产、生活带来许多不便,甚至引起重大经济损失,防覆冰涂层主要通过材料表面特殊物理化学性能与微相形貌来实现抗冰目的,这类材料需要兼具防结冰性和疏冰性,从延长结冰时间和降低冰的附着力两方面来减轻甚至消除冰雪积聚,是目前研究的热点。本文从防覆冰机理入手,深入探讨了防结冰性和疏冰性的影响因素,阐述了防覆冰涂层材料的设计与制备方面的最新进展,并对防覆冰涂层目前存在的问题与发展方向进行了分析和展望。     

透明超疏水材料的制备及其应用

超疏水材料由于其独特的非浸润性引起人们的广泛关注,近年来得到迅猛发展,各种适用于不同领域的功能性超疏水表面应运而生。其中,透明超疏水材料因其在光学领域的特殊贡献受到人们的青睐。透明疏水涂层技术对于实际应用具有重要的意义,透明涂层不仅可以满足光学器件防护的高透光率,还可以维持防护本体的基本外观,在自清洁、防污、防冰防雾、防腐蚀等领域都展示出广阔的应用前景。本文系统地阐述了超疏水表面以及其中功能性的透明超疏水表面的最新进展、表面的设计、制造和重要应用。尽管已经取得了重大进展,但是目前超疏水材料在耐久性方面还存在诸多问题,例如,容易被机械外力破坏、极端环境下表面的超疏水性质不稳定以及老化等问题,限制了透明疏水涂层技术的大范围应用。在未来的研究中,一方面继续丰富相关的理论知识,为透明疏水涂层技术的应用提供更多的理论支持,另一方面,提高涂层的透明度和机械耐久性能仍是未来研究的重中之重。     

自修复超疏水涂层材料研究进展

超疏水涂层材料具有自清洁、减阻、防雾、防黏附等特点,被广泛应用于防腐涂层、管道运输、油水分离等领域。但超疏水涂层材料在使用过程中由于物理磨损和化学腐蚀等原因易使其丧失超疏水性能,限制了其在工业中的实际应用,因此自修复超疏水涂层材料应运而生,且成为近年来的研究热点。本文综述了自修复超疏水涂层材料的最新研究进展,总结并对比了外援型自修复超疏水涂层材料和本征型自修复超疏水涂层材料的优缺点,同时对该领域的未来发展前景进行了简要展望。     

透明超疏水材料的研究进展

超疏水表面在包括自清洁、防腐、防冰和流体输送过程中的减阻等许多领域都有广泛应用,透明的超疏水表面更是在太阳能光伏电池板和其他光学领域具有自我清洁的潜在应用。本文首先介绍了透明超疏水的相关理论,然后概括了制备超疏水表面常见的方法,重点归纳总结了用于构建粗糙度的不同物质,如SiO2、 TiO2 等,并分析了其优缺点;最后,简单介绍了透明超疏水的应用前景,并对其研究方向进行了展望。     

有机硅改性聚氨酯/纳米SiO2复合超疏水涂层的制备

以4,4'-二苯基甲烷二异氰酸酯(MDI)、聚四氢呋喃醚二醇(PTMEG)、羟基封端的聚二甲基硅氧烷(HO-PDMS)、1,4-丁二醇(BDO)为原料,合成了有机硅改性的聚氨酯溶液,通过核磁共振、红外光谱技术对其结构进行表征,并研究了羟基硅油加入量对聚氨酯热稳定性、疏水性的影响.以有机硅改性的聚氨酯溶液为基体、含氟硅烷偶联剂改性的纳米二氧化硅颗粒为填料,喷涂制备超疏水涂层,研究了填料添加量对复合涂层疏水性的影响.结果表明:当硅油加入量为9 wt%,填料加入量为60 wt%时,复合涂层性能最优,水接触角为153.3°,滞后角为6.3°.经过200℃加热1 h后,仍然具有大于150°的水接触角.对复合涂层进行磨损实验与防冰测试,结果表明:该复合涂层在磨损过程中,在基底暴露之前,整个涂层基体都具有超疏水性;并且该涂层能有效降低结冰温度,延长结冰时间,具有良好的防冰性能.     

二氧化硅纳米颗粒/硅树脂复合超疏水功能涂层的制备和性能研究

将二氧化硅纳米颗粒和硅树脂制成混合液,采用喷涂法(spray-coating)制备出了具备超疏水性的复合涂层.研究了二氧化硅、硅树脂不同含量配比对涂层疏水性能的影响,结果表明复合涂层的接触角随二氧化硅含量的增加而增加.在二氧化硅含量大于3%(质量分数)时,涂层显现超疏水性;当二氧化硅含量为3%(质量分数)、硅树脂含量为7%(质量分数)时,涂层与水的接触角达到151.6°,滚动角接近0°.通过扫描电子显微镜(SEM)观察涂层表面的微观结构,发现超疏水性的涂层具备微-纳复合阶层结构,类球状突起粒径在5μm左右,类球状突起上分布纳米团聚颗粒,直径约为50 nm.这种类似荷叶表面的微(纳复合阶层结构,结合硅树脂的低表面能,使得复合涂层具备了超疏水性能.     

聚苯硫醚超疏水复合涂层的制备与性能

利用工业原料聚苯硫醚微粉和疏水性二氧化硅纳米粉末,采用喷涂法在瓷砖表面制备了疏水复合涂层.研究了热处理温度、组分配比对涂层表面形貌、粗糙度和接触角的影响,发现随着热处理温度升高,涂层表面粗糙度增大,随着疏水性二氧化硅含量的增加,由于表面聚集的疏水性二氧化硅增多,涂层疏水性增强,在热处理温度为280℃、疏水性二氧化硅与聚苯硫醚质量比为1∶1时,可获得超疏水涂层,涂层的接触角大于150°,滚落角小于4°,pH值为1～14的水溶液在其表面都具有很高的接触角.超疏水涂层具有良好的自清洁效果,并且经落沙法实验测定,超疏水涂层耐刮伤性能良好.     

仿生超疏水材料的构建及应用研究

<正>所谓超疏水表面是指与水的静态接触角>150°、滚动角<10°的固体表面。随着科技的进步和社会的发展,超疏水材料以其独特的润湿性能在印刷包装工业中具有广泛的应用前景。对自然界中天然超疏水表面微观结构的研究表明构建具有一定粗糙度的表面微观结构是获得超疏水表面的重要途径。本论文从超疏水固体表面微细结构的角度出发,提出了几种构建超疏水功能涂层更为简单、高效的制备方法,并研究了相应表面的润湿性能及在疏水涂层及油水分离方面的应用。具体研究内容如下:     

Facile designing a superhydrophobic anti-icing surface applied for reliable long-term deicing

While superhydrophobic coatings have shown promise as potential anti-icing coatings, the surface roughness of these coatings is prone to damage during repeated icing-deicing cycles. Herein, two kinds of superhydrophobic anti-icing coatings are prepared from organic resin and micro-nano particles using two strategies, and their excellent anti-icing properties are also investigated. However, superhydrophobic surface I (SF1), prepared by first strategy, cannot be used for extended periods of time due to irreversible damage to the surface roughness during the icing–deicing process. Finite element simulations and experimental studies are preformed to investigate the fatal issue of such roughness damage. In contrast, the anti-icing properties of superhydrophobic surface II (SF2), prepared by second strategy, can easily regain through a simple sandpaper abrasion treatment even the surface roughness was damaged during the icing–deicing process. These exploratory results and SF2 preparation strategy provide a facile design of anti-icing coating, and the derived restorable anti-icing coating is expected to be useful for a wide application.     

Condensation and freezing of droplets on superhydrophobic surfaces

Superhydrophobic coatings are reported as promising candidates for anti-icing applications. Various studies have shown that as well as having ultra water repellency the surfaces have reduced ice adhesion and can delay water freezing. However, the structure or texture (roughness) of the superhydrophobic surface is subject to degradation during the thermocycling or wetting process. This degradation can impair the superhydrophobicity and the icephobicity of those coatings. In this review, a brief overview of the process of droplet freezing on superhydrophobic coatings is presented with respect to their potential in anti-icing applications. To support this discussion, new data is presented about the condensation of water onto physically decorated substrates, and the associated freezing process which impacts on the freezing of macroscopic droplets on the surface.     

A study on superhydrophobic coating in anti-icing of glass/porcelain insulator

This paper focuses on the preparation of a superhydrophobic coating on glass/porcelain insulators which possess anti-icing property below freezing temperature. Inspired by lotus-effect, the fabrication of a superhydrophobic coating has two steps: the first step is to construct a hierarchical SiO₂ coating on the substrate surface, and the second step is the chemical modification of the SiO₂ coating with 1H,1H,2H,2H-Perfluorodecyltriethoxysilane (PDTS). The precursor for the hierarchical SiO₂ coating is a suspension of SiO₂ sol particles and dispersible SiO₂ powder particles. According to the TEM testing, SiO₂ sol particles prepared by sol–gel method has an average particle size about 2–5 nm, while the size of the dispersible SiO₂ particles is ca. 20 nm. The precursor was sprayed on glass/porcelain insulators, and then dried at ambient condition, finally heat-treated at 773 K for 2 h. The morphology of the superhydrophobic coating was characterized by TEM and AFM, and experimental results indicated that the coating featured [hierarchical structure consisting of both large bumps with micron-sized height (0.8 μm) and tiny papillae with the size about 30 nm] micron-sized roughness (0.8 μm) combined with nano-sized roughness (about 2 nm). Moreover, the scratch test showed that the coating tightly adhered to the surface of the glass/porcelain insulators. The superhydrophobic property of the coating was examined by a contact angle measurement, and the results demonstrated that the static water contact angle is high up to 163.6°, and the sliding angle is 1.4°. The superhydrophobic property of the coating was also confirmed by the outdoor tests in winter, and it was found that the superhydrophobic coating had the function in anti-icing, based on which the anti-icing mechanism underlying was discussed in terms of the interaction between impacting droplets and superhydrophobic surface.     

Fabrication of superhydrophobic cellulose-based materials through a solution-immersion process

An industrial waterproof reagent [(potassium methyl siliconate) (PMS)] was used for fabricating a superhydrophobic surface on a cellulose-based material (cotton fabric or paper) through a solution-immersion method. This method involves a hydrogen bond assembly and a polycondensation process. The silanol, which was formed by a reaction of PMS aqueous solution with CO 2, was assembled on the cellulose molecule surface via hydrogen bond interactions. The polymethylsilsesquioxane coatings were prepared by a polycondensation reaction of the hydroxyl between cellulose and silanol. The superhydrophobic cellulose materials were characterized by FTIR spectroscopy, thermogravimetry, and surface analysis (XPS, FESEM, AFM, and contact angle measurements). Analytical characterization revealed that nanoscale roughness protuberances uniformly covered the surface, thus transforming the cellulose from superhydrophilic to superhydrophobic with a water contact angle of 157 degrees . The superhydrophobic coatings were satisfactory with regard to both chemical and mechanical durability, and because of the transparency of the coatings the native cotton fabric displayed no changes with regard to either morphology or color. The easy availability of the materials and simplicity of this method render it convenient for mass production.     

超疏水低粘着铜表面制备及其防覆冰性能

用喷砂处理在铜片表面形成微米级丘陵状凹坑,再用表面氧化处理在铜片表面制备菊花花瓣状CuO纳米片.通过喷砂-表面氧化处理在铜片表面成功构建了微米-纳米复合结构,这种表面氟化后与水滴的接触角高达161°,滚动角低至1°,显示出优异的超疏水性和很低的粘着性.低温下,这种表面与水滴间的热量交换较小,水滴不易凝结,有效地提高了抗结霜性.抗结霜性良好的超疏水铜有望在热交换器或低温运行设备等领域获得应用,这种简便的超疏水铜表面的制备方法也给其它工程材料超疏水表面的工业化制备提供了一个思路.     

Superhydrophobic and oleophobic coatings from flower-like zinc oxide and fluorinated epoxy with good comprehensive property

Nowadays, most superhydrophobic surfaces will lose their superhydrophobic performance once they encounter oil, and adhesive strength of superhydrophobic coating is low. Therefore, the superhydrophobic coating with good oleophobicity and high adhesive strength is popular with people. A superhydrophobic and oleophobic coating is characteristic of antifouling and self-cleaning, due to the appearance of special structures, such as overhang and re-entrant. In this work, flower-like zinc oxide (ZnO) particles free of fluorine and fluorine-containing epoxy were used to establish the coating with a similar re-entrant structure. Flower-like ZnO particles were prepared by a chemical precipitation method, and the water contact angle of flower-like ZnO is up to 149 ± 1°. For the coating, flower-like ZnO particles were almost covered by fluorine-containing epoxy synthesized through click reaction so that the adhesive strength between the coating and the matrix is high, superior to some coatings in the references. The surfaces made of flower-like ZnO and fluorinated epoxy possess superhydrophobic and oleophobic properties. The contact angle of the coating for water, diiodomethane, glycerol, and glycol is 154 ± 0.7°, 138 ± 0.6°, 156 ± 0.7°, and 150 ± 0.7°, respectively. After withstanding 70 cycles under the pressure of 1 kPa, the coating is still superhydrophobic. Also, the coating possesses a good self-cleaning and anti-icing property.     

Fabrication of Stable Superhydrophobic Coatings with Furfural Acetone Resin/PTFE Composites

We describe a simple and inexpensive technique to fabricate superhydrophobic coatings with furfural acetone resin/poly (tetrafluoroethylene) (FAR/PTFE) composites. An interesting hierarchical structure with dispersed cavities and protuberances in microscale was achieved. The water contact angle (CA) of the superhydrophobic surface is 157° and the sliding angle is about 5°. The coatings can be applied to large substrates by spray coating with ease and possess high cohesional strength with the substrates. Meanwhile, the superhydrophobic coatings show long-term stability in pure water and acidic solutions with higher concentration.