纳秒激光诱导铝板表面超疏水微纳结构北大核心CSCD

提出了一种利用纳秒光纤激光快速制备超疏水铝板表面的方法,对样品表面的接触角和粗糙度进行了测量。烘烤处理激光加工后的样品,得到了一系列具有不同润湿性能的铝板表面,增加激光能量密度可得到超疏水表面。研究结果表明,增加激光能量密度除了能提高铝板表面的粗糙度,还会形成明显的微纳二级结构;空气占铝板超疏水复合接触面总面积的90%以上;纳秒激光诱导铝板超疏水表面是微纳结构和化学成分共同作用的结果。     

TC4微织构表面液滴撞击特性实验研究

为了探究不同扫描速度下激光刻蚀钛合金微织构超疏水表面的液滴撞击特性,在工业用材TC4(Ti 6Al4V)表面进行一步成型激光刻蚀后,利用扫描电子显微镜和共聚焦电子显微镜对表面形貌进行观测,利用接触角测量仪测量表面的润湿性,利用高速摄像机实验平台捕捉液滴撞击过程。结果表明,受表面微织构和表面化学性能的共同影响,扫描速度为200mm·s-1的工况下,表面的疏水性能最佳;疏水性能好的表面由于黏性耗散低,液滴的最大铺展系数较大。     

玻璃材料激光加工技术的研究进展

玻璃材料因其优良、独特的理化性能在半导体、微流控芯片、微机电系统、光通讯及光存储等新兴领域有广泛的应用。激光技术作为一种新型非接触加工方法,可以对玻璃材料表面或其内部进行高精度、高效率的微加工,在玻璃材料加工领域展现出巨大潜力。归纳了激光刻蚀、激光打孔、激光焊接及激光制备功能结构4种典型的激光加工玻璃工艺的基本原理及关键问题,指出了玻璃材料激光加工的最新研究进展、工艺水平及应用现状,其中激光刻蚀包括了激光直写刻蚀、激光诱导等离子体刻蚀与激光背部湿法刻蚀; 激光打孔包括了远红外CO₂激光打孔、超快激光打孔及改进的打孔方法;激光焊接玻璃工艺包括远红外CO₂激光焊接、纳秒激光焊接、超快激光焊接,以及激光制备表面和内部3维功能结构。同时总结了4类激光加工玻璃工艺的优缺点,分析了目前的瓶颈问题。在此基础上,对激光加工玻璃材料的发展前景进行总结和展望。     

GH3230高温合金绿光飞秒激光的刻蚀特性

飞秒激光以其超窄脉宽和超高光强等特性被广泛应用于各种金属材料的加工。本课题组采用波长为515 nm的绿光飞秒激光器对GH3230镍基高温合金进行刻蚀试验，研究了GH3230高温合金的绿光飞秒激光刻蚀阈值、刻蚀率和极限刻蚀深度。结果表明：相比于红外飞秒激光，绿光飞秒激光的刻蚀阈值明显降低，刻蚀率显著提高；与红外飞秒激光刻蚀类似，随着刻蚀次数增加，刻蚀深度增大，但当刻蚀次数增加到一定值后，刻蚀深度出现饱和现象；激光能量密度越高，极限刻蚀深度越大；改变扫描策略进行双道刻蚀时，通过增加刻缝宽度可以增大刻蚀深度；激光诱导等离子体是影响刻蚀深度的主要因素。     

皮秒激光加工工艺对微沟槽表面的疏水性研究

为了研究紫外皮秒激光在均热板基板表面刻蚀微沟槽后,不同激光工艺参数对微沟槽表面疏水性的影响规律,采用Cassie-Baxter模型进行了理论分析,并利用单因素实验法,改变激光扫描速率、激光扫描间距、光斑横向重叠次数进行实验验证.结果表明,降低固-液区域面积占比、宽度或缩短沟槽间距,均可以提升微沟槽表面的疏水性能;造成微...     

超疏水氧化锆陶瓷表面的激光加工+硅油修饰+热处理复合工艺及机理研究

氧化锆陶瓷以其优异的力学性能和生物相容性被广泛用作牙科修复材料。通过表面改性工艺调控氧化锆陶瓷的表面润湿性,可以进一步拓展其在不同领域的应用。基于此,笔者提出了一种高效、低成本的激光加工+硅油修饰+热处理复合工艺,并采用该工艺制备了超疏水氧化锆陶瓷表面。首先通过纳秒激光加工在氧化锆陶瓷表面诱导出周期性多级微纳结构,而后利用硅油异丙醇混合溶液（硅油体积分数为0.4%）修饰+低温热处理来降低激光处理后氧化锆陶瓷的表面能,制备出了表面接触角高达153.8°具有超疏水特性的氧化锆陶瓷。加工前的氧化锆陶瓷的接触角为80.4°±2.1°,展现出亲水性;经纳秒激光加工后,液滴完全浸润表面,接触角变为0°,表面转变为超亲水表面。采用硅油异丙醇混合溶液修饰+低温热处理工艺实现了表面超亲水特性向超疏水特性的转变。超疏水氧化锆陶瓷在空气环境和胶带剥离实验中分别保持了优秀的稳定性和耐久性。通过改变激光的扫描速度及扫描间距可以精准调控液滴在材料表面的润湿性和黏附性。所提方法相较于传统激光加工方法提高了制备效率,降低了生产成本,有望扩展超疏水氧化锆陶瓷在医疗领域的应用。     

纳秒激光诱导超疏水硅橡胶表面微结构的分形特性

针对纳秒激光刻蚀硅橡胶表面产生的浸润性变化现象,采用分形理论对其表面微结构的形成及浸润性的转变过程进行了研究。当输入的激光能量密度较低时,硅橡胶表面发生局部的热解,生成了具有高自相似性的大小颗粒复合状态的粗糙结构,其表面的分形维数提升而疏水性能略有增加。随着激光能量密度增加,硅橡胶上的大颗粒进一步热解至微纳米尺度的小颗粒,其表面分形维数降低,此时液滴只与表面的微纳小颗粒凸面相接触,由此形成了超疏水表面;随着激光能量密度进一步提高,累积的热效应使表面形成了板状结构和沟壑,导致其粗糙度的增大。当激光能量的输入与硅橡胶表面热解达到平衡时,其表面的粗糙结构和分形特征不再发生明显变化,由此形成了具有较高自相似性的稳定超疏水表面。研究结果对于快速制备超疏水硅橡胶表面及调控其表面微结构具有良好的指导意义。     

开关面板微纳结构的激光制备及超疏水性研究

为了解决厨房用开关面板抗油污沉积的问题, 采用飞秒激光在开关面板表面制备出微纳米复合结构表面, 实现了超疏水性, 进而减少油污沉积附着, 研究了聚碳酸酯(PC)开关面板的激光烧蚀阈值、不同激光工艺参数和微纳结构对表面浸润性的影响。结果表明, PC开关面板在515nm波段下的烧蚀阈值为1.66μJ; 当激光能量为1.6μJ、扫描速率为200mm/s、搭接率为1/3线宽时, 其表面液滴接触角为161°, 表现出超疏水特性。经激光表面处理后的PC面板具有超疏水性, 可实现表面的自清洁作用, 显示出巨大的市场潜力。     

飞秒激光仿生制备超滑表面及其应用北大核心CSCD

仿生超滑表面由于能抗各种液体甚至动植物黏附,因而具有非常重要的研究价值和广泛的应用前景。飞秒激光微加工技术具有材料普适性强、加工精度高、可控性强等特点,在制备和调控特殊浸润性表面方面具有非常突出的优势。从仿生制造的角度出发,首先介绍了飞秒激光微加工在构建和控制超疏水表面、水下超疏油表面的相关研究进展,分析了其在实际应用中的局限和不足;概述了超滑表面的制备原则及飞秒激光制备超滑表面的工艺方法,系统地总结了飞秒激光制备的各类超滑表面,及其对多种液体和气泡的操控;介绍了超滑表面的一些典型应用;最后总结和讨论了飞秒激光制备超滑表面研究和应用中存在的问题及发展前景。     

飞秒激光刻蚀CF/EP表面疏水性能研究北大核心CSCD

碳纤维/环氧树脂复合材料(CF/EP)在航空航天、交通运输、风电等领域中广泛应用,但由于长期工作在恶劣环境中,表面容易浸水、沾灰和结冰等。为改善CF/EP表面疏水性,先利用飞秒激光加工系统在其表面制备出乳突微结构,再采用白光干涉仪观测乳突微结构表面形貌,并结合接触角测量仪分析表面微结构的疏水性能;研究激光功率和微结构尺寸参数对乳突微结构及其疏水性的影响。研究结果表明:在扫描速度、脉冲频率一定的条件下,接触角与输入功率成正相关,当功率高于1.25 W时,接触角与输入功率成负相关;碳纤维/环氧树脂表面微结构的接触角随乳突半径的增大而减小,最大接触角达到139.7°;使用飞秒激光刻蚀CF/EP表面可以提高其表面疏水性能,并且乳突半径是影响CF/EP表面疏水性能的重要因素。     

Fabrication and Characterization of Superhydrophobic Surfaces with Dynamic Stability

Superhydrophobic surfaces of dynamic stability are crucial for applications in water‐repellent materials. In this work, a hierarchical structure composed of a dendritic microporous surface with nanostructured porosity is demonstrated that shows robust superhydrophobicity with dynamic stability. The hierarchical structures are obtained on both copper foils and wires by a dynamic gas‐bubble template‐assisted electrochemical deposition method. The substrates can then be modified with alkyl thiols to obtain the surface superhydrophobicity. A new kind of testing, mechanical monitor‐assisted continuous water surface strokes, is developed to reveal the dynamic stability of the as‐prepared superhydrophobic copper wires. The as‐prepared superhydrophobic copper wires can exert a high propulsive force, and particularly, show little adhesive force in the process of continuous strokes on the water surface, exhibiting robust superhydrophobicity with dynamic stability. The approach allows a strategy for the fabrication of superhydrophobic surfaces with dynamic stability, and suggests a new method to evaluate the dynamic stability of superhydrophobic surfaces.     

Design Rules for Laser‐Treated Icephobic Metallic Surfaces for Aeronautic Applications

Ice accretion on external aircraft surfaces due to the impact of supercooled water droplets can negatively affect the aerodynamic performance and reduce the operational capability and, therefore, must be prevented. Icephobic coatings capable of reducing the adhesion strength of ice to a surface represent a promising technology to support thermal or mechanical ice protection systems. Icephobicity is similar to hydrophobicity in several aspects and superhydrophobic surfaces embody a straightforward solution to the ice adhesion problem. Short/ultrashort pulsed laser surface treatments are proposed as a viable technology to generate superhydrophobic properties on metallic surfaces. However, it has not yet been verified whether such surfaces are generally icephobic under representative icing conditions. This study investigates the ice adhesion strength on Ti6Al4V, an alloy commonly used for aerospace components, textured by means of direct laser writing, direct laser interference patterning, and laser‐induced periodic surface structures laser sources with pulse durations ranging from nano‐ to femtosecond regimes. A clear relation between the spatial period, the surface microstructure depth, and the ice adhesion strength under different icing conditions is investigated. From these observations, a set of design rules can be defined for superhydrophobic surfaces that are icephobic, too.     

Fabrication of Superhydrophobic Surfaces on Engineering Materials by a Solution‐Immersion Process

Superhydrophobic surfaces on engineering materials are prepared via a convenient solution‐immersion method. The binary geometric structures at the micro‐ and nanometer scale bestow superhydrophobic properties on the surfaces. The surfaces show stable superhydrophobicity even in many corrosive solutions, such as acidic or basic solutions over a wide pH range, and also in salt solutions. The procedure is time‐saving, inexpensive, and fairly facile to carry out. It is expected that this facile technique will accelerate the large‐scale production of superhydrophobic engineering materials with new industrial applications.     

三级微纳超疏水表面的超快激光复合制备及防除冰性能研究

本文针对超疏水表面的防除冰性能,采用超快激光结合化学氧化的复合制备方法,开发了一类新的三级微纳超疏水表面结构,这类结构由微米锥阵列支撑结构以及在其上密集生长的金属氧化物纳米草结构和弥散分布的微米或亚微米花结构组合而成。经过表面改性后,这类三级微纳结构具有优异的超疏水性,其接触角可超过160°,滚动角在1°以内。对这类三级微纳超疏水表面的防结冰性能进行研究后发现,在冷凝和低温环境下,该类超疏水表面存在合并诱导自跳跃以及分级冷凝的现象,分级冷凝不仅可使表面上的一级冷凝液滴在高湿度环境下依然保持Cassie状态,还能使液滴在结冰前脱离表面,因此具有较好的防结冰性能;此外,由于表面三级微纳粗糙结构中捕获的空气囊具有较好的隔热作用,因此该超疏水表面具有良好的延迟结冰性能,其延迟异质形核的时间达到了52 min 39 s。最后,本文对三级微纳超疏水表面的疏冰性能进行了研究,结果表明:三级微纳超疏水表面的冰粘附强度仅为6 kPa,约为未经处理的铝合金表面的1/40;经过10次推冰测试后,该超疏水表面的冰粘附强度依然不超过20 kPa,说明该表面具有良好的机械耐久性,应用潜力巨大。     

Stable superhydrophobic surfaces induced by dual-scale topography on SU-8

SU-8 is a photosensitive resist widely used for the fabrication of MEMS and lab-on-a-chip devices, as well as of model structures for testing wetting theories. In this work, superhydrophobic surfaces are fabricated on SU-8 by combining micro- and nano-sized structures formed by means of lithography and plasma etching, respectively. It is found that nanotexturing of the micropatterned SU-8 surfaces is essential in enhancing surface hydrophobicity and rendering the surfaces water repellent (i.e. minimizing contact angle hysteresis). The proposed method will be shown to be of paramount importance for the fabrication of mechanically stable and robust superhydrophobic SU-8 surfaces with low aspect ratio microstructuring.     

无源LCD液晶面板制造新工艺探讨

无源LCD面板及触摸屏制作过程通常采用湿法刻蚀的方法来制作ITO电极图形,在生产过程中要用到光刻胶、刻蚀液、脱膜液等对环境有污染的材料,而对这些生产过程中的污染物要进行环保处理后才能排放。且工艺过程长,加工成本较高,加工后的ITO图形存在明显的缺陷,如ITO电极线条边缘有毛刺等。文章介绍了一种用激光刻蚀的方法来代替传统的湿法刻蚀方法,来加工用于无源LCD面板及触摸屏等平板显示器的ITO电极图形方法,缩短了工艺过程以及节约了成本、提高了产品质量。     

微秒激光制备超疏水表面及抑霜性能实验研究北大核心CSCD

为解决航空器在各种运行环境环境中可能出现的霜冰影响问题,利用微秒脉冲激光在钛合金表面制备了超疏水表面,并通过微观形貌、表面元素组成、润湿性和结霜实验等对超疏水效果和抑霜性能进行了分析表征。实验结果表明,微秒激光制备的不同扫描间距的微纳结构表面均达到了超疏水效果,其中扫描间距为0.2 mm的表面接触角可达159°,其表面激光作用形成的大量细小颗粒以及溅落的碎屑等形成的亚微米和纳米级结构,为空气中有机疏水基团提供了丰富的结合位点,二者共同带来了表面优良的超疏水性能,表面生长的霜层薄,霜枝较高,十分有利于外界作用清除。本方法可为航空领域霜冰问题的解决提供一定参考。     

Hierarchical Superhydrophobic Surfaces Fabricated by Dual‐Scale Electron‐Beam‐Lithography with Well‐Ordered Secondary Nanostructures

Recent studies on superhydrophobic surfaces have revealed the important roles of structural hierarchy in the overall properties of these surfaces. Here, a novel, versatile, and efficient technique is introduced for fabricating macroscopic hierarchical superhydrophobic surfaces with both well‐defined primary microstructures and well‐ordered secondary nanostructures using electron‐beam lithography. With this technique, the engineering capability of controlling the size, shape, and distribution of the secondary‐features is demonstrated, which allows a systematic and quantitative study of the individual effects of these parameters. Superhydrophobic surfaces produced by this new technique exhibit two distinctive wetting behaviors, high and low adhesion. The structural characteristics and structure‐property relations of each of those two regimes are discussed.     

A Mechanistic Study of Wetting Superhydrophobic Porous 3D Meshes

Superhydrophobic, porous, 3D materials composed of poly(?‐caprolactone) (PCL) and the hydrophobic polymer dopant poly(glycerol monostearate‐co‐?‐caprolactone) (PGC‐C18) are fabricated using the electrospinning technique. These 3D materials are distinct from 2D superhydrophobic surfaces, with maintenance of air at the surface as well as within the bulk of the material. These superhydrophobic materials float in water, and when held underwater and pressed, an air bubble is released and will rise to the surface. By changing the PGC‐C18 doping concentration in the meshes and/or the fiber size from the micro‐ to nanoscale, the long‐term stability of the entrapped air layer is controlled. The rate of water infiltration into the meshes, and the resulting displacement of the entrapped air, is quantitatively measured using X‐ray computed tomography. The properties of the meshes are further probed using surfactants and solvents of different surface tensions. Finally, the application of hydraulic pressure is used to quantify the breakthrough pressure to wet the meshes. The tools for fabrication and analysis of these superhydrophobic materials as well as the ability to control the robustness of the entrapped air layer are highly desirable for a number of existing and emerging applications.     

Corrosion‐Resistant Superhydrophobic Coatings on Mg Alloy Surfaces Inspired by Lotus Seedpod

Superhydrophobic surfaces are widely found in nature, inspiring the development of excellent antiwater surfaces with barrier coatings isolating the underlying materials from the external environment. Here, the naturally occurring superhydrophobicity of lotus seedpod surfaces is reported. Protective coatings that mimic the lotus seedpod are fabricated on AZ91D Mg alloy surfaces with the synergistic effect of robust superhydrophobicity and durable corrosion resistance. The predesigned titanium dioxide films are coated on AZ91D by an in situ hydrothermal synthesis technique. Through sonication assisted electroless plating combined with a self‐assembling method, the densely packed Cu‐thiolate layers are uniformly plated with robust adhesion on the Mg alloy substrate, which function as a superhydrophobic barrier that can hold back the transport of water and corrosive ions contained such as Cl^?. Notably, the two extreme wetting behaviors (superhydrophilicity and superhydrophobicity) as well as corrosion resistance and improved corrosion resistance can be easily controlled by removal of the hydrophobic materials (n ‐dodecanethiol) at elevated temperature (350 °C) and modifying them at room temperature for 18 cycles, indicative of exceptional adhesion between the superhydrophobic coating and the underlying AZ91D Mg alloy.