金属基超疏水表面的制备技术研究新进展

在简要介绍超疏水表面相关理论的基础上,着眼于金属基超疏水表面制备中关键技术的发展态势,重点分析了不同类型制备方法在制备工艺要点、微纳米拓扑结构设计与构建、低表面能材料修饰、表面性能提升效果等方面的研究进展,系统梳理了金属基超疏水表面在自清洁、金属防腐、水下减阻等领域的应用现状及影响其机械稳定性的关键要素,探讨了金属基超疏水表面制备技术在发展过程中需要面临的核心挑战和需注重解决的问题,希望为实现大面积金属基超疏水表面的工程化应用提供参考。     

化学/电化学法制备金属基超疏水表面研究进展

主要从增材和减材两个方面总结了国内外金属基超疏水表面的制备现状,重点讨论了化学法、电化学法以及其组合法等加工方法,并阐述了各方法的优缺点。最后提出金属基超疏水表面制备技术的展望,未来研究应在坚持工艺过程简单、成本低廉、易于实现、可控性好等原则的基础上,重点提高超疏水表面的可靠性和工作寿命。     

超疏水换热器抑霜/化霜性能的实验研究

超疏水表面可有效抑制结霜,但其在换热器尺度的制备及抑霜/化霜研究较为缺乏,限制了超疏水改性技术在解决空气源热泵结霜问题上的应用。为获取超疏水换热器的抑霜/化霜性能,通过对常规翅片管换热器进行溶液刻蚀和表面氟化,整体化制备了超疏水换热器。搭建了换热器结霜/化霜实验系统,对比研究了亲水、常规和超疏水换热器的结霜与化霜特性。结果表明：在相同实验工况下结霜60 min,超疏水换热器的结霜量比亲水和常规型分别减少了18.0%和38.6%;化霜时,得益于霜层从翅片表面直接剥落,超疏水换热器的化霜时间短、能耗低。     

激光刻蚀法制备超疏水自清洁铝合金表面

金属表面超疏水性能的研究是当今多学科研究的热点与难点,针对金属表面超疏水以及自清洁性能的研究现状,通过激光加工方法在粗糙铝合金表面构筑一种具备超疏水自清洁特性的网格状多级结构.采用扫描电子显微镜(S E M)、激光共聚焦显微镜(L S C M)以及光学接触角测量仪等表征试样表面的微观结构、三维形貌和润湿特性.结果表明:制备表面具有网格状多级结构,结构展现凹槽、坑、飞溅状或颗粒状的复杂形貌和复合尺度特征,表面具有优异的超疏水性能,接触角达到150.6°.同时自清洁性能测试发现超疏水铝合金表面展现良好的低黏附以及自清洁性能,这种复合性能对铝合金在脱附减阻等领域的应用研究提供一定的参考意义.     

支撑剂表面疏水处理方法的研究

对支撑剂表面进行疏水处理可以使其在支撑裂缝、防砂的同时起到降低油田产出水的目的。疏水表面处理方法共分为普通疏水及超疏水两大类。普通疏水表面制备方法分为表面活性剂、有机硅材料、含氟材料3个方面;超疏水表面制备方法分为溶胶-凝胶法、电纺法、模版法、层层自组装法和刻蚀法。对其处理结果等进行对比,结合现场已有的抑水支撑剂应用情况,提出将疏水表面制备方法应用于支撑剂。使用表面活性剂对石英表面进行疏水性改造实验,发现阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)的效果最好,接触角由13.7°增大到73.2°。此时表面张力为48.88mN/m,吸附量为0.292mg/g。     

典型植物非光滑疏水表面的理想模型

通过对植物非光滑表面疏水特性的分析,把疏水表面分为4类:超亲水表面、中等亲水表面、中等疏水表面、超疏水表面。从能量平衡的角度论证了超亲水表面、超疏水表面能量传递符合Cassie模型,中等亲水表面、中等疏水表面能量传递符合W enzel模型,并从许多的植物疏水表面中筛选出4种典型的几何非光滑表面原型,分别构建了凸包型、凹坑型、圆锥型、柱型的理想疏水表面的数学模型,这将为工程仿生脱附的疏水表面设计与制造提供理论依据。     

白铜超疏水表面的构建及耐蚀性能的研究

超疏水膜具有良好的防腐蚀性能,能够有效地延长金属制品的使用寿命,提高经济效益.选取白铜作为研究对象,采用化学刻蚀氧化自组装法进行超疏水膜表面的制备.通过交流阻抗和极化曲线法,在模拟海水条件下,利用三电极体系对超疏水表面的耐蚀性能进行了研究和测定.结果表明,所制备的白铜超疏水表面的接触角达到了154°,在3.5%的NaCl溶液中的缓蚀效率有99.1%,具备较高的超疏水性能和耐蚀性能,且其表面具有微纳米级的树枝状结构.     

纺织品自清洁整理研究进展

介绍了超疏水表面和光催化表面的自清洁原理和制备方法,在两种技术的基础上阐述了超疏水光催化协同自清洁表面的研究现状,并且对如何提高自清洁性能提出了策略,对纺织品自清洁整理技术的发展前景和趋势进行了展望.     

静电纺丝法制备超疏水微纳米纤维的研究进展

超疏水纤维膜因其独特表面性能成为功能表面领域的研究热点。静电纺丝技术作为一种新兴技术,设备操作简单,可高效调控纳米纤维表面形貌,实现微米-纳米双级结构自组装,从而获得超疏水微纳米纤维表面材料,利用此技术所制备微纳米纤维表面形貌及其物理性质接近于天然纤维超疏水材料。首先简要介绍了超疏水表面自清洁的基础理论和静电纺丝法的技术原理,进而重点对近期静电纺丝技术制备超疏水表面材料的最新研究进展进行了综述与分析。     

层流状态下超疏水表面流场建模与减阻特性仿真研究

在充分发展层流状态下对具有规则微观结构的超疏水表面流场进行数值仿真研究,分析了超疏水表面流场的减阻特性.针对超疏水表面微观结构特点,采用Cassie接触模型,对计算域利用结构化网格进行划分,采用VOF多向流模型进行数值仿真.研究表明:超疏水表面凹槽附近产生压差阻力导致凹槽内部形成低速漩涡,产生推动效应与涡垫效应;超疏水表面减阻率随凹槽槽宽增大而增大,受凹槽深度影响不显著,矩形凹槽比V形凹槽与U形凹槽有更好的减阻效果.     

液滴碰撞不同湿润性表面的行为特征

为了探究湿润性对液滴撞击行为特性的影响,制备超亲水、亲水、超疏水高黏附、超疏水低黏附4类湿润性表面.利用直径为1.96、2.61、3.06 mm的液滴,在不同的高度下开展液滴碰撞4类湿润性表面的实验.结果表明,在不同We下,液滴碰撞特性受撞击表面湿润性的影响较大,在亲水以及超亲水表面主要表现为铺展特性,但在超亲水表面扩展更显著;在超疏水低黏附以及高黏附表面主要表现为弹跳特性,但当表面为低黏附时,液滴主要表现为完全弹跳.在We-Re坐标下,4类表面各自的液滴碰撞特性可以划分为差异明显的不同铺展或者弹跳现象.4类表面各自的扩展系数β随无量纲时间τ的变化趋势随We的变化基本保持不变,但β的最大值随We的增大而增大.     

Comparative Study of Structure and Property Changes in Corrosive Media for Self-cleaning Superhydrophobic Magnesium Alloys

Magnesium alloys with superhydrophobicity are constructed by controlling rough surface structure and grafting long hydrophobic alkyl chains. Changes of morphology, phase structure, chemical composition as well as wettability, corrosion resistance of superhydrophobic magnesium alloy upon immersing in corrosive media are investigated comparatively. Meanwhile, the contaminating particles on as-prepared superhydrophobic surfaces can be taken away easily by rolling water droplets. Therefore, the results show that as-prepared superhydrophobic magnesium alloys exhibit enhanced corrosion resistance and self-healing performance. Finally, anti-corrosion and self-cleaning mechanisms are deduced. It can be concluded that it is an effective strategy of preparing superhydrophobic surfaces for improving the corrosion resistance and selfcleaning performance of magnesium alloys.     

Preparation of PDVB/TiO_2 composites and the study on the oil-water separation and degradation performances

The traditional superhydrophobic materials are not ideal for treating residual pollutants after oil-water separation. In this paper, a simple and economical method was developed for the fabrication of multi-functional superhydrophobic materials PDVB_x/TiO_2 composites, through in situ polymerization. The performance of the superhydrophobic composite was studied. The results showed that the low surface energy of PDVB_(2.5)/TiO_2 composite with the micro-nano scale roughness would result in excellent superhydrophobicity. In addition, the PDVB_(2.5)/TiO_2 composite exhibits optimum effect on the degradation of methyl orange(MO) with the degradation efficiency of 97.8%. What is more, the applications of the composite materials could be expanded to other fields, such as the degradation of drug ciprofloxacin hydrochloride(CIP). Finally, we expanded the application of the PDVB_x/TiO_2 composites to tribology, and found its excellent performance in reducing wear and antiwear.     

亲-疏水两层结构表面强化蒸汽冷凝传热

为了研究蒸汽在不同润湿性结构表面上的冷凝传热性能,基于协同排液思想和仿生理念,利用化学刻蚀法制备超疏水-超亲水两层结构表面：一层为超疏水表面,另一层为经双氧水氧化的烧结乳突结构表面,2层之间为空腔. 研究组合结构、过冷度和冷却水体积流量对冷凝传热的影响. 实验结果表明：亲-疏水组合结构表面的冷凝传热系数最高. 当过冷度为5.0 K时,组合结构表面的冷凝传热系数分别为光滑铜表面和单一超疏水表面的4.8、1.8倍. 冷凝形成的液滴在向乳突运动的过程中主要受到2个驱动力：接触乳突结构后受到的拉普拉斯压差作用力、乳突内部孔隙所产生的毛细吸力. 组合表面的冷凝传热系数随冷却水体积流量的增大和过冷度的增大而逐渐减小.     

Transition of super-hydrophobic states of droplet on rough surface

Twelve samples with periodic array square pillars microstructure were prepared on the silicon wafer by plasma etching techniques, on which space b of the square pillars increased from 5 to 60 m. In order to study the effect of b on the wettability of the rough surface, the effects of apparent contact angle (CA) and sliding angle (a) of the droplet on the rough surface were measured with the contact angle meter. The results show that the experimental values of CA well agree with the classical wetting theory and a decreases with the increase of b. Two drop shapes exist on the samples' surface, corresponding to the Cassie state and the Wenzel state respectively. The contact state in which a drop would settle depends typically on the size of b. On the role of gravitation, the irreversible transition of a drop from Cassie state to Wenzel state should occur at a certain space of the square pillars. Since the transition has implications on the application of super-hydrophobic rough surfaces, theoretically, the prediction of wetting state transition on square pillar array micro-structured surfaces provides an intuitionistic guidance for the design of steady superhydrophobic surfaces.     

A facile method to fabricate surfaces showing superhydrophilicity in air and superhydrophobicity in oil

The changes of the wettability of the solid surfaces have attracted massive attention due to their important practical implications in numerous fields. As a new subject, the research on the wettability under the different environments is still in its early stage. So the fundamental research must be performed for the practical applications under different environments. However, it is seldom that the comprehensive wettability of a surface in air, in water and in oil has been reported. In this paper, the authors investigated the wettability of the stainless steel mesh coated with polyurethane in the above three different environments. The surface of the uncoated mesh was found to be hydrophobic in air, but the surface of the coated mesh was superhydrophilic in air. More interestingly, the surfaces of the coated meshes were superoleophilic in water and superhydrophobic in oil. Due to the coated meshes with these wettabilities were fabricated via a facile two-step method, the presented method may be adopted for large-scale industrial production, in various fields, such as icing prevention or the oil-field industry.     

用于固液界面减阻无氟超疏水表面制备新方法

现阶段超疏减阻表面常用低表面能的氟化剂制备不绿色环保,为实现超疏水减阻表面的无氟化,提出一种可用于固液界面减阻的无氟铝合金超疏水表面制备新方法.首先,采用化学腐蚀技术在铝合金基底上快速制备微纳量级表面粗糙结构,再利用天然松香溶液和炭黑悬浊液进行表面修饰改性处理,替代传统氟化物.在表征上,分别采用扫描电子显微镜(SEM)、接触角测量仪和X射线能谱分析(EDS)来分别表征微观结构尺寸、表面润湿性和元素分析.通过不断优化表面结构和修饰溶液浓度,在铝合金样品上制备出接触角为155°,滚动角为1.38°处于Cassie模型状态的超疏水表面.结果表明:所构建的无氟超疏水表面经受80次浸没取出循环完整性良好,此外在速度为1.4 m/s连续水滴冲击3 h后仍保持良好的超疏特性;通过减阻冲刷实验装置测试,在0.5～3.5 m/s冲刷流速范围内,本方法制备的无氟超疏表面可达到20%～30%减阻率,从而验证了新方法在超疏减阻应用中的有效性.整个制备过程简单、成本低廉且无氟环保,利于规模化生产应用.