三角紫叶酢浆草叶面的超疏水性

三角紫叶酢浆草叶面有很好的超疏水性,水滴在其表面的接触角约为150°,滚动角约为15°。研究发现,在三角紫叶酢浆草的叶面,分布有微纳米二元复合阶层结构的"星型"微凸体,微凸体之间有大量凹槽和空隙,复合阶层结构表面能吸附一层空气膜,液滴与其表面的接触是液、固、气的复合接触。此外,植物的叶面有低表面能的蜡状物,微纳米级的复合阶层结构及其表面的低表面能物质的协同效应使其表面显示出优异的超疏水性能。该研究有望为仿生超疏水材料的制备提供有益的启示与借鉴。     

微结构与表面修饰对二氧化硅多孔薄膜疏水性能的影响

通过引入聚乙二醇(PEG)改性传统二氧化硅(SiO2)溶胶,得到了粒径分布较宽且粒径可控的溶胶。比较了六甲基二硅氮烷(HMDS)溶胶内修饰和薄膜表面修饰以及溶胶粒径对SiO2薄膜疏水性能的影响。采用动态光散射粒度仪定量测试了二氧化硅溶胶老化过程中粒度的变化,用原子力显微镜、接触角测试仪、红外光谱仪、紫外-可见-近红外分光光度计分别对薄膜的表面形貌、表观静态接触角、薄膜成分及透光率等进行了测量。结果表明:PEG的添加可有效增大溶胶粒度从而增大薄膜的粗糙度,提高薄膜的疏水性。表面修饰效果受修饰方式和SiO2粒径影响,粒径较小时有利于溶胶内修饰,粒径较大时有利于对薄膜修饰。经过表面修饰剂(HMDS)的气氛处理得到了接触角为152°的超疏水薄膜,而且相比溶胶内修饰可以减小薄膜透光率的损失。     

液相法制备具有双尺寸粗糙度的超疏水铜表面

基于简单的液相法,以硫代硫酸钠和氯化铜为原料在铜片表面上构筑了具有微/纳米双尺寸粗糙度的硫化铜膜.用X射线衍射(XRD)仪、扫描电镜(SEM)、能量色散X射线(EDX)光谱仪及光学视频接触角仪对处理前后的铜表面进行了表征和分析.处理后的超亲水铜表面经硬脂酸修饰后具有超疏水效应,静态接触角高达161°,5μL水滴滚动角低至2.5°左右.超疏水性能归因于表面具有双尺寸粗糙度和低表面能的硬脂酸.该方法简单,无需复杂制备过程和苛刻设备,所得超疏水铜表面具有优异的不粘附性、长时间储存的稳定性和一定的耐摩擦性能.     

TiO_2纳米薄膜油下超疏水/超亲水性的可逆调控

采用简单的提拉镀膜法制备了一种TiO_2纳米薄膜,在油相介质中,水滴在其表面的接触角约为160°,呈现出油下超疏水状态.当在湿度为20%的空气环境下对TiO_2纳米薄膜进行紫外光照射(60 min)后,该薄膜由油下超疏水状态转变为油下超亲水状态.对紫外光照射后的TiO_2纳米薄膜在100℃下热处理70min后,该薄膜又恢复到了初始的油下超疏水状态.因此,通过紫外光照射和热处理可实现TiO_2纳米薄膜油下超疏水性与油下超亲水性的可逆调控. TiO_2纳米薄膜油下水超浸润性可逆调控主要归因于薄膜表面的微纳米结构和化学组成变化的协同作用.     

双级微结构上二氧化硅粒子对微注压成型PP表面润湿特性的影响

提出一种柔性复制法,采用微注射压缩(μ-ICM)成型具有微拓扑结构的仿生聚丙烯(PP)表面.通过复制模板上的双级微结构,所成型的PP材料表面上呈现具有锥形顶面的双级微结构,即微棱和高纵横比的微锥体.由于微锥体之间的间隙较大,水滴浸润其间隙的上方,这使该表面呈现中等黏附的超疏水特性.在μ-ICM过程中,涂覆在模板上的二氧化硅纳米粒子(SNPs)被转移到熔体中,并牢牢附着于微结构表层,赋予其表面亚微米或微米粗糙度,形成多层次微结构.在附着有亲水SNPs的微结构上,高表面自由能使水滴完全浸润微锥体之间的间隙,表面的水接触角为161.9°、滚动角大于90°,呈现极高黏附的超疏水特性(花瓣效应);在附着有疏水SNPs的微结构上,水滴受疏水SNPs的排斥而减弱与表面之间的黏附作用,表面的水接触角为163.5°、滚动角为3.5°,呈现极低黏附的超疏水特性(荷叶效应).     

溶胶凝胶法制备超疏水二氧化硅涂膜及其表面润湿行为

采用溶胶-凝胶法以正硅酸乙酯(TEOS)和甲基三乙氧基硅烷(MTES)为前驱体制备超疏水SiO2涂层。红外光谱(FTIR)和热重分析(TGA)表征合成SiO2的化学组成,通过透射电镜(TEM)和扫描电镜(TEM)观察制备SiO2的结构形貌,扫描电镜(SEM)和原子力显微镜(AFM)观察SiO2涂膜的表面形貌,通过测试水接触角(WCA)讨论SiO2涂层的表面微观结构与其表面疏水性能的关系。结果表明以TEOS和MTES为共前驱体可以制备得到表面带-CH3基团的SiO2溶胶,SiO2溶胶在老化过程中纳米SiO2粒子由于自组装作用形成草莓状微米-纳米双微观结构,这种结构赋予SiO2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,与SiO2表面疏水性的-CH3基团共同作用形成类荷叶超疏水结构。     

超疏水聚硅氧烷涂层的制备及其性能

采用溶胶-凝胶法,以甲基三乙氧基硅烷(MTES)为有机硅前驱体,通过酸-碱催化水解-缩合得到聚有机硅氧烷凝胶,经浸涂-提拉成膜技术在玻璃表面制备超疏水聚硅氧烷涂层。通过红外光谱(FT-IR)、水接触角(WCA)和场发射扫描电子显微镜(FE-SEM)等分析技术对涂层进行了结构表征、疏水性测试和表面形貌观察。结果表明,涂层内部形成带有甲基和残余硅羟基基团的网络结构。当n(MTES)∶n(EtOH)∶n(H2O)分别为1∶35∶8和1∶45∶8时,在室温制备的涂层对水的接触角可分别高达160°和162°,滚动角均低至7°,并且涂层在250℃以下的热处理过程中,其疏水性基本保持不变。FE-SEM观察证实了涂层表面分布着许多孔径为0.5～1.0μm的微孔和粒径为50～100 nm的纳米颗粒聚集体,具有微-纳米尺寸相结合的双重结构。此外涂层还具有较高的透明性、对腐蚀性液体具有超疏水性。研制得到的超疏水涂层有望用于玻璃、织物、金属和塑料等基底表面作为保护和防腐蚀涂膜。     

超声辅助制备超疏水聚丙烯表面花瓣状微纳结构

超疏水微纳结构表面广泛应用于自清洁、防冰、抗菌、柔性传感等领域,但其制备工艺仍面临一定的挑战.以阳极氧化铝(AAO)膜为模板,采用热压印在聚丙烯(PP)表面成型了规整的纳米结构阵列.对纳米结构阵列进行超声处理,在超声空化作用下,PP表面纳米结构转变为类花瓣状微纳结构.结果表明,经超声处理后的微纳结构PP表面的接触角从152.3°上升至160.0°,滚动角从11.5°降低至1.8°,表面黏附力从75μN降低至38μN,呈现典型的超疏水低黏附特性且其自清洁效应明显.采用模板法与超声辅助相结合的方法制备超疏水微纳表面具有方便快捷、成本低廉、效果显著的优点,有望应用于工业生产领域.     

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.     

染料敏化的TiO2纳米管薄膜的光电浸润性

采用阳极氧化法在钛箔表面制备TiO2纳米管阵列, 并在其表面修饰N3染料(Ruthenium dye)作敏化剂, 用氟硅烷来提高表面疏水性, 获得超疏水薄膜. SEM测定结果表明, 纳米管薄膜具有各向异性浸润结构, 同时阳极氧化的非均匀性增加了表面的粗糙度. UV-Vis吸收光谱及电化学阻抗谱结果表明, 薄膜具有优异的光电性能. 通过施加超过一定阈值的电压, 液滴在薄膜表面由超疏水状态转变为亲水状态. 利用光电协同激励作用时, 阈值电压比单独使用电激励时降低了10 V, 这是使用高效的N3染料光电敏化层的结果.     

含氟硅丙烯酸酯乳液超疏水膜中疏水基团的梯度分布与表面微观结构研究

利用含氟疏水基团的梯度分布,结合草莓形纳米SiO2粒子提供的双重粗糙表面,制备了具有类"荷叶效应"的超疏水涂膜,水接触角达(174.2±2)°,滞后角几乎接近0°.通过原子力显微镜、扫描电镜和水接触角的测试对膜表面形貌及疏水性能进行了表征;探讨了其表面微观结构与表面疏水性能的关系.草莓形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,使水滴与涂膜表面接触时能够形成高的空气捕捉率,这种微观结构与疏水基团的梯度分布相结合,赋予了含氟硅丙烯酸酯乳液涂膜表面超疏水性能.     

Effects of contact angle hysteresis on ice adhesion and growth on superhydrophobic surfaces under dynamic flow conditions

In this paper, the icephobic properties of superhydrophobic surfaces are investigated under dynamic flow conditions using a closed-loop low-temperature wind tunnel. Superhydrophobic surfaces were prepared by coating aluminum and steel substrate plates with nano-structured hydrophobic particles. The superhydrophobic plates, along with uncoated controls, were exposed to a wind tunnel air flow of 12 m/s and ?7 °C with deviations of ±1 m/s and ±2.5 °C, respectively, containing micrometer-sized (～50 μm in diameter) water droplets. The ice formation and accretion were observed by CCD cameras. Results show that the superhydrophobic coatings significantly delay ice formation and accretion even under the dynamic flow condition of highly energetic impingement of accelerated supercooled water droplets. It is found that there is a time scale for this phenomenon (delay in ice formation) which has a clear correlation with contact angle hysteresis and the length scale of the surface roughness of the superhydrophobic surface samples, being the highest for the plate with the lowest contact angle hysteresis and finest surface roughness. The results suggest that the key for designing icephobic surfaces under the hydrodynamic pressure of impinging droplets is to retain a non-wetting superhydrophobic state with low contact angle hysteresis, rather than to only have a high apparent contact angle (conventionally referred to as a “static” contact angle).     

Modification of wetting properties of laser-textured surfaces by depositing triboelectrically charged Teflon particles

Hydrophilic laser-textured silicon wafers with natural oxide surfaces were rendered hydrophobic by depositing electrostatically charged submicrometer Teflon particles, a process termed as triboelectric Teflon adhesion. Silicon surfaces were micro-textured (～5 μm) by laser ablation using a nanosecond pulsed UV laser. By varying laser fluence, micro-texture morphology of the wafers could be reproduced and well controlled. Wetting properties of the triboelectrically charged Teflon-deposited surfaces were studied by measuring apparent static water contact angles and water contact angle hysteresis as a function of substrate roughness and the amount of Teflon deposited. A similar study was also performed on various micro-textured silicon carbide surfaces (sandpapers). If the average substrate roughness is between 15 and 60 μm, superhydrophobic surfaces can be easily formed by Teflon deposition with water contact angle hysteresis less than 8°. This environmentally benign solvent-free process is a highly efficient, rapid, and inexpensive way to render contact-charged rough surfaces hydrophobic or superhydrophobic.     

Creation of low hysteresis superhydrophobic paper by deposition of hydrophilic diamond-like carbon films

The creation of low hysteresis superhydrophobic paper is reported using a combination of oxygen plasma etching and plasma deposition of an 80 nm non-fluorinated, hydrophilic diamond-like carbon (DLC) coating. The DLC has an equilibrium (flat surface) contact angle (θ _e ) of 68.2° ± 1.5°, which is well below the 90° contact angle that is typically believed to be a prerequisite for superhydrophobicity. Coating of paper substrates with the DLC film yields an advancing contact angle of 124.3° ± 4.1°, but the surface remains highly adhesive, with a receding contact angle <10°. After 60 min of plasma etching and DLC coating, a low hysteresis, superhydrophobic surface is formed with an advancing contact angle of 162.0° ± 6.3° and hysteresis of 8.7° ± 1.9°. To understand the increase in contact angle and decrease in hysteresis, atomic force microscopy and optical profilometry studies were performed. The data demonstrates that while little additional nanoscale roughness is imparted beyond the first 5 min of etching, the roughness at the microscale continually increases. The hierarchical structure provides the appropriate roughness to create low hysteresis superhydrophobic paper from a hydrophilic coating.     

Fabrication and characterization of superhydrophobic silica nanotrees

Superhydrophobic silica nanotrees were obtained by sol–gel method with hybrid silica sol and jelly-like resorcinol formaldehyde resin. Rough surfaces were obtained by removing the organic polymer at high temperature. After the films with rough surface were modified by trimethylchlorosilane (TMCS), the wettability of the film changed from superhydrophilic to superhydrophobic. The surface roughness of the silica nanotrees film is about 20 nm, and it is transparent and superhydrophobic with a water contact angle higher than 150°.     

超疏水碱式碳酸钴纳米线薄膜的制备及抗腐蚀性

以镍为基底,采用水热法在其表面制得碱式碳酸钴纳米线薄膜,用十二烷基硫醇进行表面修饰后其表现出超疏水性,水滴在其表面的接触角达到152.3°,滚动角接近5°.研究结果表明,薄膜表面微纳米阶层结构及低表面物质的协同作用使其呈超疏水性.与普通镍片和硫醇修饰前的碱式碳酸钴纳米线薄膜相比,超疏水碱式碳酸钴纳米线薄膜具有更好的抗腐蚀性.相关研究有望为超疏水金属表面的制备及其抗腐蚀性研究提供思路.     

以砂纸为模板制作聚合物超疏水表面

报道了一种聚合物材料超疏水表面的简便制备方法. 以不同型号的金相砂纸为模板, 通过浇注成型或热压成型技术, 在聚合物表面形成不同粗糙度的结构. 接触角实验结果证明, 聚合物表面与水的接触角随着所用砂纸模板粗糙度的增加而加大, 其中粒度号为W7和W5砂纸制作的表面与水的接触角可超过150°, 显示出超疏水性质. 多种聚合物使用砂纸为模均可制备不同粗糙度及超疏水的表面, 本征接触角对复制表面浸润性的影响从Wenzel态到Cassie态而变小. 扫描电镜结果表明, 不规则形状的砂纸磨料颗粒构成了超疏水所需要的微纳米结构的模板.     

Fabrication and mechanical durability of a superhydrophobic copper surface with morphological development from hydrothermal reaction

The superhydrophobic surface on copper is fabricated by using a simple hydrothermal reaction and subsequent perfluorosilane treatment. The micro‐structured and nano‐structured surface was directly obtained through the hydrothermal reaction of copper sheets with sulfur at 180 °C for 12 h, resulting in the formation of copper sulfide film on the copper substrate. The chemical composition of this film was confirmed using X‐ray photoelectron spectroscopy. After copper sulfide film is treated by perfluorosilane, the superhydrophobic surface with static water contact angle of 153 °C and a low contact angle hysteresis is achieved. The superhydrophobic surface shows strong mechanical stability and can effectively protect the copper substrate. Copyright © 2016 John Wiley & Sons, Ltd.     

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.     

Fabrication of superhydrophobic surface by hierarchical growth of lotus-leaf-like boehmite on aluminum foil

Hierarchical growth of boehmite film on the aluminum foil was carried out via a facile solution-phase synthesis route. The resultant film is composed of three-dimensional microprotrusions assembled from well aligned nanoneedles. Such dual scale micro-/nanostructures are highly similar with those of lotus leaves. The resultant surface after hydrophobization exhibits a water contact angle of 169° and a sliding angle of ～4° for a 5 μL droplet, which is ascribed to the combination of the dual scale roughness at the micro- and nanometer scale and the low surface energy of stearic acid coating. The obtained film possesses relatively good adhesion to the aluminum substrate and keeps superhydrophobicity after the ultrasonic treatment or long-term storage in spite of the partial loss of it superhydrophobic ability after abrasion test.