Construction of Renewable Superhydrophobic Surfaces via Thermally Induced Phase Separation and Mechanical Peeling

We report a simple preparation method of a renewable superhydrophobic surface by ther-mally induced phase separation (TIPS) and mechanical peeling. Porous polyvinylidene fluo-ride (PVDF) membranes with hierarchical structures were prepared by a TIPS process under different cooling conditions, which were confirmed by scanning electron microscopy and mer-cury intrusion porosimetry. After peeling off the top layer, rough structures with hundreds of nanometers to several microns were obtained. A digital microscopy determines that the surface roughness of peeled PVDF membranes is much higher than that of the original PVDF membrane, which is important to obtain the superhydrophobicity. Water contact angle and sliding angle measurements demonstrate that the peeled membrane surfaces display super-hydrophobicity with a high contact angle (152°) and a low sliding angle (7.2°). Moreover, the superhydrophobicity can be easily recovered for many times by a simple mechanical peel-ing, identical to the original superhydrophobicity. This simple preparation method is low cost, and suitable for large-scale industrialization, which may offer more opportunities for practical applications.     

Simple treatment of cotton textile to impart high water repellent properties

We describe two methods to impart the water repellency for the surface of cotton fabric, using a commercially available and a laboratory synthesized fluoroalkylsiloxanes. To characterize the wettability and the durability of water repellent properties of hydrophobic coating produced, we have studied the advancing water contact angles, rolling angles and the evolution of water contact angle in time during a continuous contact of the surface with the water drop. The quality of the coatings was also assessed after the washing procedure. The analysis of the wettability of hydrophobized fabrics indicated that a better effect, leading to the superhydrophobic state of the surface, was observed when the surface relief of the fabric with the coating is determined by not only the structure and braiding of the fabric, but also the additional elements of texture created by the aggregates of molecules of hydrophobic agent.     

Superhydrophobic and icephobic surfaces prepared by RF-sputtered polytetrafluoroethylene coatings

A superhydrophobic and icephobic surface were investigated on aluminum alloy substrate. Anodizing was used first to create a micro-nanostructured aluminum oxide underlayer on the alloy substrate. In a second step, the rough surface was coated with RF-sputtered polytetrafluoroethylene (PTFE or Teflon^®). Scanning electron microscopy images showed a “bird's nest”-like structure on the anodized surface. The RF-sputtered PTFE coating exhibited a high static contact angle of ∼165° with a very low contact angle hysteresis of ∼3°. X-ray photoelectron spectroscopy (XPS) results showed high quantities of CF₃ and CF₂ groups, which are responsible for the hydrophobic behavior of the coatings. The performance of this superhydrophobic film was studied under atmospheric icing conditions. These results showed that on superhydrophobic surfaces ice-adhesion strength was 3.5 times lower than on the polished aluminum substrate.     

自清洁功能的超疏水微/纳米结构铜网用于高效的分离油水

本文介绍了一种简便的方法制备n-十二烷基三甲氧基硅烷@三氧化钨包覆的超亲油超疏水的铜网.所制备的铜网显示了较为突出的超亲油和超疏水性能,该铜网的水接触角大约有154.39°,而油接触角接近于0°.实验利用了各种有机溶剂和水的混合物对所制备网膜进行分离性能测试,结果表明所得涂覆铜网的油水分离效率高达99.3V,并且水的通量大约为9962.3 L·h~(-1)·m~(-2).所制备的铜网具有良好的稳定性,经过10次分离循环后分离效率仍然保持在90%以上.由于三氧化钨优异的光催化降解性能,所制备铜网具有自清洁能力.因此,被润滑油污染的网膜可以恢复超疏水性,而这种自清洁性使所制网膜可以反复用于油水分离.     

生物光子晶体蝴蝶翅膀表面的凝结液滴憎水性

采用环境扫描电子显微镜(ESEM)观测了蝴蝶翅膀的微观结构, 揭示了蝴蝶翅膀颜色的各向异性特征. 采用高速摄像仪实时动态观察了蝴蝶翅膀的水凝结浸润特性, 分别探究了蝴蝶翅膀在水平、 不同倾斜角度以及在振动条件下的水凝结的憎水性. 基于微观结构, 对蝴蝶翅膀的水凝结憎水特性进行机理阐述. 定量描述了其表面的黏滞特性, 并基于蝴蝶翅膀的微观结构效应阐述了翅膀表面水凝结的憎水性机制.     

反应离子刻蚀和自组装分子膜构建硅基底疏水与超疏水表面

采用反应离子刻蚀技术在Si(100)表面加工微米级圆柱阵列, 采用自组装技术分别制备了3种硅烷自组装分子膜. 结果表明, 采用反应离子刻蚀构建出的4种微米级圆柱阵列结构规整, 其直径为5 μm, 高度为10 μm, 间距为15~45 μm. 沉积自组装分子膜后, 试样表面的水接触角显著增大, 其中沉积1H,1H,2H,2H-全氟癸基三氯硅烷(FDTS)自组装分子膜接触角最大, 1H,1H,2H,2H-全氟辛烷基三氯硅烷(FOTS)次之, 三氯十八硅烷(OTS)最小. 测得的接触角大于150°时接近Cassie方程计算的接触角, 而小于150°时接近Wenzel方程计算的接触角. 改变圆柱阵列的间距和选择不同的自组装分子膜, 可以控制表面接触角的大小. 原子力显微镜(AFM)观测结果显示, 沉积自组装分子膜可以产生纳米级的团簇. 由微米级圆柱阵列和纳米级自组装分子膜构成的表面结构使Si试样表面接触角最大可达156.0°.     

Fabrication of Superhydrophobic Surface with Different Metal Films on Aluminum Alloy

A simple technique was developed for the fabrication of a superhydrophobic surface on the aluminum alloy sheets. Different hierarchical structures(Ag, Co, Ni and Zn) were formed on the aluminum surface by the galvanic replacement reactions. After the chemical modification of them with fluorination, the wettability of the surfaces was changed from superhydrophilicity to superhydrophobicity. Scanning electron microscopy(SEM), energy dispersive spectrometry(EDS) and water contact angle measurement were performed to characterize the morphological characteristic, chemical composition and superhydrophobicity of the surfaces. The as-prepared superhydrophobic surfaces showed a water contact angle as high as ca.160° and sliding angle as low as ca.3°. We hope the method to produce superhydrophobic surface can be used in many fields.     

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.     

光响应性超疏水偶氮苯自组装多层膜的制备及性质研究

近年来,偶氮苯类化合物的光学顺反异构现象已引起人们的广泛关注[1~7].在紫外光照射下,偶氮苯由反式结构转变为顺式结构,引起分子的偶极矩发生变化,导致分子的吸收光谱、尺寸及表面能等均发生变化[7].偶氮苯表面能的改变可引起其表面浸润性发生变化.据文献[1~4]报道,偶氮苯膜在紫外光照射前后接触角最大改变了11°.浸润性是固体表面的一个重要特性,主要受固体表面的化学组成和微观几何结构(粗糙度)影响[8~11].通常,与水的接触角大于150°的表面称为超疏水表面;而与水的接触角小于5°的表面称为超亲水表面.本文以2-(4-偶氮苯基苯氧基)丙烯酸…     

聚酯织物表面耐用超疏水涂层的制备及在油水分离中的应用

使用在含有甲基MQ(M:单官能团Si-O单元R₃SiO_1/2, Q:四官能团Si-O单元SiO₂)硅树脂与疏水SiO₂的二甲苯溶液中浸渍的方法,在聚酯织物表面制备了耐用超疏水涂层。经过处理后,微米级聚酯纤维表面被紧密的疏水纳米颗粒包裹,通过这种方法降低了纤维的表面能。聚酯织物展现出良好的超疏水特性,与水滴的静态接触角为156°,滚动角为5°。得到的超疏水聚酯织物在机械磨损、酸碱环境及紫外线照射条件下,表现出了良好的稳定性。此外,用超疏水聚酯织物作为过滤材料得到的油水分离效率达99%以上。该方法为大面积工业制备超疏水织物提供了新的思路。