激光纹理化调控材料表面疏水性能研究进展

超疏水表面由于具有减阻、抗污、防水等独特性能,广泛应用于日常生活、军事、工业等场景,材料表面的微纳结构及化学成分对其超疏水性能有着重要影响。激光纹理化技术由于具有加工分辨率高、加工方式灵活、可加工材料多等优势,可用于制备疏水性能精确可控的表面微纳结构,在制造超疏水表面方面有着广阔的应用前景。首先,介绍了激光纹理化的作用机理,综述了常用的激光纹理化方式,如激光直接写入法、激光干涉图案化法及激光诱导周期性结构法等,并介绍了激光参数对微纳结构的影响。根据表面微纳结构的形貌、周期及尺寸特点对激光纹理化制备的表面分层微纳结构进行了总结归纳,包括覆盖随机纳米结构或激光诱导周期性结构的微沟槽、微网格、微柱及微峰,重点介绍了分层微纳结构的制备方式及微纳结构对疏水性的影响。总结了提高分层微纳结构表面疏水性的后处理方式,包括环境老化、表面化学改性及热处理等,并介绍了后处理方式调控疏水性的作用机理。最后,对采用激光纹理化技术制备超疏水表面的应用前景进行了展望。     

飞秒激光双光子聚合三维微纳结构加工技术

飞秒激光双光子聚合微纳加工技术作为重要的三维微纳结构制备手段，已成为国际前沿研究热点。该技术利用激光与物质相互作用的双光子非线性吸收效应和阈值效应，可以突破经典光学理论衍射极限，实现纳米尺度的激光加工分辨力，在三维功能性微纳器件制备领域正在发挥着十分重要的作用。本文在介绍飞秒激光双光子聚合三维微纳加工技术的光物理和光化学过程基本原理的基础上，重点回顾人们在改善加工线宽及分辨力、提高加工效率等方面的研究进展与发展概况。该技术所制备的各种微光学器件、集成光学器件、微机电系统以及生物医学器件，不仅充分展示了飞秒激光双光子聚合三维微纳加工技术的高空间分辨力和真三维加工特点，也为其在相关前沿领域的应用提供具有启发性的思路。最后，对该技术实现高精度、高效率、低成本、大面积、多功能的三维微纳结构加工所存在的挑战和未来发展方向，进行了讨论和展望。     

飞秒激光直写加工SERS基底及其应用

表面增强拉曼光谱(Surface-enhanced Raman spectroscopy,SERS)是一种高灵敏度、高分辨率的分子识别技术，在多个领域具有非常重要的应用价值。飞秒激光直写作为一种新兴的低成本、高分辨率、高灵活性的微纳加工方法，在制备SERS基底领域得到了广泛的应用。本文重点概述了四种飞秒激光直写制备SERS基底的加工方法，主要包括飞秒激光双光子还原、飞秒激光切割金属、飞秒激光切割-溅射、飞秒激光3D打印。文章简单介绍了各方法制备SERS基底的性能与应用场景，阐述了飞秒激光直写加工在制备SERS基底中的优势，旨在为今后相关研究提供参考。     

表面形貌对润湿性及抗附着性能的影响

为研究表面形貌对表面润湿性和抗附着性能的影响,采用激光刻蚀技术制备点阵微结构和仿生贝壳表面网格微结构,将SiO2纳米粒子涂覆在微结构上制备微纳结构。研究表明,Ti6Al4V合金表面经激光刻蚀后由亲水变为超亲水状态。经低表面能修饰后,点阵微结构表面符合Wenzel模式的疏水状态,而网格微结构表面符合Wenzel模式的超疏水状态。在点阵和网格微结构上涂覆SiO2形成微纳结构表面均符合Cassie模式的超疏水状态,且网格结构表面的接触角更大,滚动角更小。浅海挂板实验显示,微生物粘膜附着量由多至少的顺序为:超亲水状态的点阵微结构表面亲水的抛光表面超亲水状态的仿生网格微结构表面符合Cassie模式的超疏水表面。     

包装材料表面超疏液性能耐久性及其提高方法

海量油墨、涂料、油漆、胶粘剂、沥青等的包装金属桶罐由于内部粘附属于危险固废且难于处理。酸奶、果酱、牙膏等的包装由于粘附不便于分类回收。材料表面超疏液性能源于表面微纳多级粗糙结构和低表面能。制约超疏液材料应用的瓶颈是表面微纳结构制备工艺复杂和力学强度低导致的耐久性差。本文总结提出了增强超疏液性能耐久性的四类技术方法:具有自我修复功能的超疏表面,SLIPS表面,具有形状记忆的微纳结构和提高表面微纳结构本身的力学强度。具有良好耐久性的包装材料有广阔的应用空间,可以解决包装废弃物回收和利用的关键难题。     

超疏水表面微纳结构设计与制备及润湿行为调控(Ⅰ)

超疏水表面因其优异的自洁排水性能可望在高科技领域和日常生活等方面有美好的应用前景.目前通过对荷叶表面微纳结构仿生已达到在亲水材料上制备超疏水表面的准商业化水平.然而,超疏水表面现有制备方法一般都工艺复杂和费用高昂,同时其超疏水性与其他材料性能很难相容,限制了其实际应用.对此,特别需要深入理论研究,优化设计表面微纳结构.同时充分利用外界作用调控其润湿行为,实现其在某些高科技领域的率先应用.针对超疏水表面研究的这些关键问题,重点评述了当前超疏水表面理论研究特别是表面几何设计方面的最新进展,总结了目前国内外制备超疏水表面的流行技术方法,进而讨论了利用外界作用调控超疏水行为的可能性.     

光/电响应型超滑表面的激光加工制备

受到自然界的猪笼草启发,超滑表面受到了许多关注.本文通过激光加工技术在石墨烯和聚偏氟乙烯的复合材料表面(G@PVDF)进行烧蚀,采用热旋涂法将石蜡材料均匀地填充于网格状沟槽内部.利用共聚焦显微镜(CLSM)和扫描电子显微镜(SEM)表征激光加工后沟槽的形貌与深度,利用UV3600以及红外热成像仪测试样品的光吸收以及光热...     

表面微纳结构的特殊功能及制备方法研究进展

通过构建表面微纳结构和制备纳米涂层可使材料表面获得特殊功能。主要综述了表面微纳结构的特殊功能和制备表面微纳结构和纳米涂层的主要方法和加工技术。首先，介绍了表面微纳结构在超疏水、光学超透镜和减摩耐磨方面的应用；其次，分别阐述了光刻技术、激光加工技术、自组装技术、增材制造技术(3D打印)、沉积法和溶胶凝胶法等表面微纳结构和纳米涂层的加工方法的研究进展；最后，总结了表面微纳结构及纳米涂层的不同制备方法存在的问题和发展趋势。     

飞秒激光加工微纳光学器件

光学器件正在向着小型化、集成化以及柔性可变形等方向发展，基于集成微纳光学器件的光学系统以其较低的功耗、快速的响应时间以及高信息容量等优势脱颖而出。然而目前的高精度微纳加工手段如聚焦离子束(focused ion beam,FIB)刻蚀、半导体光刻等工艺复杂，且缺乏灵活性。飞秒激光作为一种非接触、高精度、高脉冲强度的“冷”加工工具在微纳加工方面受到格外青睐。本文首先阐述了飞秒激光加工微纳光学器件的背景及相关机理，然后讨论了提高飞秒激光加工分辨率的各种方法，接着综述了基于飞秒激光的多种先进加工手段，其后总结了近年来飞秒激光加工微透镜、光栅、光波导以及光子晶体方面的代表性研究进展。最后，本文概括了飞秒激光加工微纳光学器件研究领域所面临的挑战以及未来发展方向。     

秒激光双光子微纳加工技术及其在光子学微器件制备中的应用

飞秒激光可以与包括玻璃、陶瓷、半导体、金属、塑料、树脂等各类物质产生相互作用,其相互作用原理不同,加工方法也不同。利用非线性光学效应——双光子吸收的飞秒微纳加工技术是最独特也是最具有应用前景的微纳加工技术。利用显微物镜将飞秒激光聚焦到加工介质时激光光强在焦点处呈三维空间分布,双光子吸收过程仅产生在具有足够激光强度的微小区域,通过控制激光光强可以调节双光子吸收的产生范围,在适当的激光强度时,可以突破光学衍射极限的限制,将双光子吸收过程控制到远小于激光波长甚至纳米尺度范围,从而达到进行纳米加工的目的。飞秒激光双光子微纳加工技术具有真三维、一次成型及高加工分辨率的特点,是三维微纳结构制备的理想工具之一。通过“理论计算-计算机辅助图形设计-微纳激光制造“这样一个简单的流程可以实现制备可设计的复杂三维微细结构,因此在光子学微器件、微机电系统等领域具有巨大的应用前景。最近几年双光子微细加工技术也已成功地应用到功能性光子学器件中。在制备基于光子晶体带隙原理的三维光子元器件及其立体集成方面,飞秒激光双光子方法具有无可比拟的优势。我们研究小组利用碳硅烷树状大分子修饰的激光染料与光聚合制备的光固化树脂,采用双光子聚合微加工技术制...     

激光微纳制造太阳能海水淡化材料研究进展

海水淡化技术在解决水资源短缺的问题上起着重要的作用,其中太阳能海水技术的研究#更是备受关注.激光微纳制造技术作为一种先进、便捷的加工方法,近年来在制备海水淡化材料领域取得了一定的研究成果.本文以太阳能海水淡化技术以及激光加工技术作为研究背景,根据研究材料的多样性,从材料的构成本质出发,将近年来关于激光微纳制造海水淡化材...     

Thermal training of functional surfaces fabricated with femtosecond laser pulses

The effect of thermal training of a functional surface fabricated by means of femtosecond laser surface processing on a crystalline silicon (c-Si) surface is found for the first time. Hydrodynamic and thermal properties of the c-Si surface are revealed to be considerably modified by femtosecond laser processing and follow-up thermal training. The carried out experimental studies of wetting, evaporation, and boiling processes on the thermal trained laser processed surface open up ample opportunities in creation of tailored functional surfaces for micro/optoelectronic devices and power engineering applications.     

飞秒激光与晶体材料相互作用的研究进展

综述了飞秒激光与各种晶体材料作用的现象,如双光子、多光子非线性吸收致上转换发光现象,各类微结构、色心结构等;阐述了飞秒激光与各种晶体的作用机制及在各方面的应用;展望了飞秒激光与晶体材料作用的应用前景.     

Functional Surfaces with Enhanced Heat Transfer for Spray Cooling Technology

In this study the effects of nano/microstructuring and surface chemistry on wettability, evaporation rate and the Leidenfrost temperature are experimentally investigated. The functional surfaces with two alternative patterns were originally fabricated via direct femtosecond laser surface processing of polished silicon wafer in air at a fluence slightly above ablation threshold. The droplet lifetime method was used to measure the evaporation rate of a water droplet (4.5 μL) at surface temperatures of 25–350°C and to determine the Leidenfrost temperature. Generally, after processing the functional surfaces with hierarchical surface morphology demonstrate enhanced wetting behavior, evaporation rate enhancement and positive shifts in the Leidenfrost temperature. The functional surfaces with a microgrooved surface pattern, extensively covered by flake-like nanostructures, exhibit strong superhydrophilicity, resulted in a significant temperature-dependent enhancement of evaporation rate (up to 6 times) and an increase of about 30°C in the Leidenfrost temperature relative to the polished surface. The functional surfaces with a microcratered surface pattern being only hydrophilic demonstrate a nearly twofold temperature-independent enhancement of evaporation rate. Thermostability tests showed the heating of the functional surfaces above 340°C to be resulted in a drastically deteriorated wettability and a reduction of evaporative heat transfer performance under repeated experiments.     

Femtosecond Laser Technology for Solid-State Material Processing: Creation of Functional Surfaces and Selective Modification of Nanoscale Layers

Information on the rapidly increasing use of modification of solid-state materials surfaces by femtosecond laser pulses at moderate intensities (around 0.1–10 TW/cm²) is presented as applied to creation of functional surfaces with tailored thermophysical, hydrodynamic, and mechanical properties and in application to selective modification and removal of nanoscale (1–100 nm) layers of bulk and thin-film multilayer materials. The problems in obtaining functional surfaces with the externally controllable wetting behavior of superhydrophobic surfaces showing a self-cleaning effect and superhydrophilic surfaces with a controlled Leidenfrost temperature, critical heat flux, and heat transfer coefficient are considered for heat-transfer enhancement during the evaporation and boiling of the working fluid. Data on the hardening of the surface layer of structural materials and the synthesis of diamond-like films are given. The methods for the precision selective removal of nanoscale films and surface modification with the formation of subnanoscale structures are considered.     

Excimer laser-induced microstructural changes of alumina and silicon carbide

Surface treatments with a KrF excimer laser were applied on alumina and silicon carbide ceramic materials. Results on the surface modifications induced by laser were related to the processing parameters: laser fluence (1.8 and 7.5 J/cm²), number of laser pulses (1 to 500), frequency (1 to 120 Hz), pulse duration (25 ns), sample speed under the laser beam and working atmosphere. It was ascertained that alumina can be laser treated under air, while silicon carbide needs an inert atmosphere to avoid surface oxidation. Microstructural analyses of surface and cross section of the laser processed samples evidenced that at low fluence (1.8 J/cm²) the surface of both ceramics is covered by a scale due to melting/resolidification. At high fluence (7.5 J/cm²) there are no continuous scales on the surfaces; material is removed by decomposition/vaporisation and the depth of material removal is linearly dependent on the number of pulses. On alumina surface, a network of microcracks formed, while on silicon carbide different morphologies (flat and rugged areas, deposits of debris and discontinuous thin remelted scales) were detected. The evolution of surface morphology and roughness is discussed with reference to composition, microstructure and physical and optical properties of the two tested ceramics and to laser processing parameters.     

飞秒激光加热引起相变过程的研究进展

飞秒激光因其在烧蚀固体材料时的独特机制,具有高精度高微结构的能力,表现出广阔的工程应用前景,因此近年来关于飞秒激光的研究受到广泛关注.报道了近年来飞秒激光的实验测定方法,综述了用于研究由激光加热引起的微尺度热传导的几种数值模型和方法,着重描述了分子动力学数值模拟方法,分析总结了现有的烧蚀机制,并展望了其发展前景.     

Influence of liquid environments on femtosecond laser ablation of silicon

Liquid-assisted ablation of solids by femtosecond laser pulses has proved to be an efficient tool for highly precise microfabrication, which evokes numerous research interests in recent years. In this paper, we systematically investigate the interaction of femtosecond laser pulses with silicon wafer in water, alcohol, and as a comparison, in air. After producing a series of multiple-shot craters on a silicon wafer in the three types of environments, surface morphologies and femtosecond laser-induced periodic surface structures are comparatively studied via the scanning electron microscope investigations. Meanwhile, the influence of liquid mediums on ablation threshold fluence and ablation depth is also numerically analyzed. The experimental results indicate that the ablation threshold fluences of silicon are reduced by the presence of liquids (water/alcohol) and ablation depths of craters are deepened in ambient water. Furthermore, smoother surfaces tend to be obtained in alcohol-mediated ablation at smaller shot numbers. Finally, the evolution of the femtosecond laser-induced periodic surface structures in air, water and alcohol is also discussed.