Selective no loss transportation of water droplets based on the superhydrophobic surfaces with controllable high water adhesion

Superhydrophobic ZnO surfaces with controllable high water adhesion have been fabricated by combining both construction of ZnO structures on zinc substrates and the subsequent modification of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (PDTMS). Different surface morphologies were obtained on the zinc substrates by changing the concentration ratio of (NH₄)₂S₂O₈/NaOH and temperature during the hydrothermal process. After being modified with PDTMS, the as-prepared surfaces show analogous superhydrophobicity but controllable high water adhesion, which ranges from 3 to 5 μL, 8 and 10 μL. Based on the different high water adhesion on the superhydrophobic surfaces, the selective no loss water transportation with different volumes has been achieved. We believed that the results reported here would be potentially used in microfluidic systems to manipulate the liquid droplets.     

疏水疏冰涂层的研究进展

介绍了描述液滴润湿性的Young、Wenzel和Cassie模型,概述了静、动态疏水性与疏冰之间的关系,综述了疏水疏冰涂层的制备方法,以及冰粘接强度的主要影响因素和测量方法,指出了疏水疏冰涂层将来的研究方向.     

微纳米结构对聚合物超疏水表面润湿性的影响

对聚合物超疏水表面疏水原因的理论分析及其超疏水表面常用的制备方法进行了总结,并从热力学角度评述了关于超疏水状态的两种理论模型:Wenzel模型和Cassie模型,分析了微纳米结构对聚合物超疏水表面表观接触角的影响.     

聚乙烯基超疏水材料的制备及研究进展

主要介绍了超疏水性能的基本原理,及以聚乙烯材料为基体制备超疏水材料的方法,包括自下而上、自上而下和两者结合等方法,并指出了聚乙烯基超疏水材料的应用前景和挑战。     

Capillary bonding of wet surfaces - the effects of contact angle and surface roughness

Capillary bonding of wet solids through a water film is common and important for a variety of problems. An existing experimental technique for the measurement of capillary bonding forces was improved and used to show how fractional wetted area and capillary bonding force vary with water 'tension' for glass, polyethylene, and aluminum on porous ceramic. The effects of contact angle and roughness were explored. The results show that increasing the contact angle clearly reduces the capillary bonding, but the effects of surface roughness were much more complicated. Roughness can increase or decrease capillary bonding, depending on the exact conditions.     

铜基超疏水表面防覆冰/抗霜冻特性分析

超疏水表面具有良好的防覆冰性能,有望改善低温条件下设备和设施的可靠性。本文采用氨气腐蚀法,制备具有微纳结构的铜表面,通过低表面能氟硅烷修饰后,金属铜表面表现出超疏水特性,其水接触角可达152.1°。利用电镜扫描、接触角测量、结冰和结霜实验分别对超疏水铜表面的表面结构、湿润性能和防覆冰性能进行研究。结果表明,超疏水表面的防覆冰/抗霜冻性能不仅与表面的粗糙度有关,还受液滴在固体表面的湿润状态的影响。当液滴在具有微-纳米结构的超疏水表面处于Cassie状态时,液滴与金属表面的接触面积小,液滴结冰速率较慢,金属表面同时具有较好的防覆冰和抗结霜性;而当液滴在金属疏水表面处于Wenzel状态时,霜晶与固体表面的接触面积增加,加快霜层的生长,金属表面的抗结霜性明显降低。     

环氧树脂涂层表面亲水性对微藻黏附性能的影响

在固体材料表面黏附成膜是微藻细胞的一种生理特性。近些年基于微藻生物膜的生物过程,如生物膜贴壁培养和防附着技术受到了很多关注。微藻在固体材料表面的黏附受藻细胞与材料表面之间的相互作用的影响,建立黏附强度与材料表面性质参数间的关系对于通过材料选择来强化或控制微藻生物膜具有非常重要的意义。本工作的目的是揭示和明确材料亲疏水性对微藻黏附的影响,提出了一种双酚A环氧(EP)树脂表面亲疏水改性的方法。通过将亲水性的二乙醇胺(DEA)或疏水性的聚甲基聚硅氧烷(PMHS)加入到EP树脂中反应,EP树脂表面水接触角在36.80?~98.34?范围内可通过加入不同量的DEA或PMHS实现任意可调,材料的表面水接触角与DEA或PMHS加入量之间有线性关系。重要的是这种改性方法获得的材料,其形貌、结构、表面粗糙度等表面性质几乎没有变化,从而在研究和关联微藻黏附量与材料表面亲疏水性(表面水接触角)之间的关系时可以排除亲疏水性之外的其他表面性质的影响;其次,考察了小球藻和栅藻在不同亲疏水性材料表面的黏附行为,结果表明小球藻和栅藻在亲水性和疏水性材料表面均能黏附成膜,但在亲水性材料表面黏附更多更快;建立了微藻最大黏附容量与材料表面接触角之间关联关系,表明微藻最大黏附容量随材料表面水接触角的增大而线性降低,栅藻的表面黏附容量比小球藻大。     

有机–无机杂化超疏水涂层的制备

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、硅丙树脂为成膜物质,制备了有机-无机杂化超疏水材料.在对用该材料获得超疏水涂层的研究中,考察了硅丙树脂的含量,比值n(MTES)/n(TEOS)、n(C_2H_5OH)/n(TEOS)和n(NH_3·H_2O)/n(TEOS)对涂层性能的影响.测试结果表明,当硅丙树脂加入量占总物料量的25%(质量分数),摩尔比n(TEOS)∶n(MTES)∶n(C_2H_5OH)∶n(NH_3·H_2O)为1∶4∶30∶10时,涂层具有良好的疏水性和均匀的外观结构,涂层静态水接触角可达156°.     

体相超疏水材料及其在大气污染控制领域的应用研究进展

体相超疏水材料因其优异的疏水性能,可广泛应用于工业防锈、管道运输、光电材料、建筑材料、纺织等领域,成为目前功能材料的研究热点之一。本文首先针对体相超疏水材料的结构特性及制备方法进行了综述。其次,针对体相超疏水材料在对挥发性有机物（VOCs）、NO_x和二氧化硫（SO₂）的净化与检测、对二氧化碳（CO₂）的捕集和还原等大气污染检测与控制领域的应用进展进行了概述。在此基础上,一方面对现有典型气体污染物控制技术的特点及其存在的问题以及体相超疏水材料与现有大气污染控制技术相结合所具备的优势进行了阐述;另一方面,对超疏水材料目前存在的耐久性差、制备过程复杂、制备原料昂贵且污染大等缺点,对体相超疏水材料的改进及应用提出了展望。     

辐射吊顶表面冷凝液滴脱落尺寸分析

通过对超疏水纯铜样品和4种经过不同表面改性处理的铝合金样品的冷凝实验,系统地研究了表面特性不同的辐射吊顶表面冷凝液滴的脱落尺寸。结果表明,超疏水表面合并诱导脱落的液滴半径不足300 μm,而且尺寸相近的微小液滴（半径之比在1.0～1.5）合并后易于发生液滴脱落。根据能量守恒原理对液滴合并过程进行了理论分析,结果表明随着合并前两液滴半径之比的增大,液滴合并脱落的阻力,黏附功和黏性耗散相比于合并后释放的表面能均变得显著,从而导致液滴合并脱落的概率减小。常规辐射吊顶表面上重力诱导脱落的液滴半径随机分布在2.0～6.0 mm,但在表面的后退角和前进角所确定的上、下限范围内。因此,超疏水处理后的辐射吊顶大幅减小了冷凝液滴的脱落尺寸,可显著降低其表面结露风险。     

基于改性纳米二氧化硅构筑棉织物超疏水表面

本文以γ-氨基丙基三甲氧基硅烷(APTMS)为改性剂,对纳米二氧化硅进行表面改性,并将其整理到棉织物上,随后利用十六烷基三甲氧基硅烷(HDTMS)对织物进行修饰,通过两步法获得棉织物超疏水界面.探讨反应条件对改性纳米SiO2的影响,并对改性纳米SiO2和整理后棉织物进行测试表征.结果表明,当温度为30℃,正硅酸四乙酯(rEOS)浓度为3％和APTMS浓度为2％,氨水用量为2 mL时,制备的改性纳米SiO2溶胶平均粒径为65.88nm,PDI为0.096,分散性较好.两步法整理后的棉织物接触角为150.36°,滚动角为8°,实现了超疏水效果,并且洗涤20次后仍具有一定疏水性.     

Contact angle and wettability of hybrid surface-treated metal adherends

Adhesion performance of adhesively bonded metal joints with aluminum and stainless steel was much dependent on the surface treatment of the adherends. This work was aimed at optimizing hybrid surface treatments to improve wettability of metal surfaces and strength of adhesive metal joints, which was a combination of mechanical, chemical, and energetic surface treatment methods. The surface free energies and wettability of hybrid surface-treated metal adherends were measured for different treatment conditions with abrasion, grit blast, sulfuric acid etching, phosphoric acid anodizing, silane treatment, plasma treatment, and flame treatment. The surface morphology and chemical composition of the metal adherends were investigated by scanning electron microscopy and X-ray photoelectron spectroscopy and the bond strengths of the single-lap joints composed of aluminum and stainless steel adherends were measured with respect to hybrid surface treatment conditions. From the experiments, an effective hybrid surface treatment condition was suggested for metal surfaces with super-hydrophilic characteristics. Also, the failure mode of adhesive metal joints was evaluated by photo-surface analysis method.     

阳极氧化法快速制备低粗糙度铝基体硬超疏水表面

借助阳极氧化法和氟化处理技术对铝表面进行改性。以Na3PO4水溶液为电解液在铝表面加工出粗糙蜂窝状结构,再以具有低表面能的氟硅烷为改性剂对铝表面的粗糙结构进行改性。结合扫描电子显微镜、能谱仪、接触角测量仪、Vickers显微硬度（HV）测量仪和三维表面轮廓仪对加工后的铝表面进行表征。结果表明：当加工时间为8 min时,...     

基于模板热压法制备超疏水柱状结构表面

超疏水表面材料在生产生活中具有重要的应用价值,其制备的关键在于构建合适的表面微结构。以多孔阳极氧化铝表面为模板,高密度聚乙烯为压印热塑材料,进行常压工况下的热压印,制备出三维柱状结构表面,表面形貌规整有序,通过调节模板结构参数实现对柱状结构尺寸的精确调控。测试结果显示,制备的不同微结构尺寸的柱状结构表面接触角均在150°以上,具有优异的超疏水性能。     

Enhancement of polymer film adhesion using acid-base interactions determined by contact angle measurements

Quantitative correlations among surface chemical composition, acid-base thermodynamics, adhesion strength, and locus-of-failure are demonstrated. Four types of functional Teflon surfaces were prepared: two acidic (containing hydroxyl and carboxyl groups), and two basic (containing acetyl and dinitrobenzoate groups). X-Ray photoelectron spectroscopy (XPS) and attenuated total reflection infrared (ATR-IR) spectroscopy were used to characterize the molecular structure of the surface region. Contact angle adsorption isotherms were determined using phenol as an acidic probe and tetrahydrofuran (THF) as a basic probe. The carboxylated surface had a higher molar ?H^ab with basic THF than the hydroxylated surface, and neither surface had any interaction with the acidic phenol probe. The acetylated surface behaved as a base, interacting with phenol but not with THF, while the dinitrobenzoyl surface had both acidic and basic character. Adhesion tests were carried out in the 180° peel mode using post-chlorinated poly(vinyl chloride) as a model acidic adhesive between pairs of each type of film. The two surfaces with basic character had significant peel strengths, while the two acidic surfaces had very low peel strengths. Scanning electron microscopy (SEM) of the basic failure surfaces showed significant plastic deformation of the Teflon polymer, while the acidic failure surfaces showed no deformation. XPS analysis of the failure surfaces confirmed interfacial failure for the acid-acid pairs, and bulk FEP failure for the acid-base pairs. These results demonstrate directly and quantitatively the enhancement of adhesive bond strength through acid-base interactions.     

超疏水近红外吸收涂层的制备及性能表征

以纳米 SiO2为微纳结构改性剂、聚二甲基硅氧烷(PDMS)为粘合剂、Sm2O3为功能颜料,通过合理的涂层结构设计,采用刮涂法制备得到具有超疏水特性的 PDMS/Sm2O3复合涂层.分析探讨了 PDMS 和 Sm2O3配比(质量比)、纳米SiO2添加量及表面微纳结构层对涂层性能的影响规律.结果表明,PDMS和Sm2O3...     

Fabrication of superhydrophobic surfaces based on PDMS coated hydrothermal grown ZnO on PET fabrics

Abstract

Wetting behavior of Zinc Oxide (ZnO) based nanomaterials has been the subject of intense investigations and is an active research field for various engineering applications and modifying the surface wettability of ZnO is of great interest. In this study, one-dimensional (1?D) semiconducting ZnO nanorods are grown on a superhydrophobic polyethylene terephthalate (PET) fabric using a hydrothermal method. A facile polydimethylsiloxane (PDMS) coating is applied onto the ZnO grown PET fabrics to improve the hydrophobicity. A wide range of characterization techniques such as field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), UV-vis spectroscopy and contact angle measurement are used to explore the morphology and wetting behavior of the as-prepared samples. The measured water contact angle (WCA) is >150° indicating its superhydrophobicity. This study reports an efficient way to obtain highly hydrophobic semiconducting ZnO grown on PET fabric, which can be of great interest for many future applications.     

超疏水性涂层的研究进展

简述了超疏水性表面的基本原理,分别从低表面能材料和涂层表面微细粗糙结构的构建两个方面,对超疏水性涂层的制备技术和最新成果进行了概括,并展望了其应用前景。