利用Langmuir-Blodgett技术构筑表面微结构的方法

由于表面纳/微结构在微电子和生物学等领域有着广泛的应用前景,其构筑方法引起了人们越来越多的关注。目前已经发展出了多种表面纳/微结构的构筑方法,然而在大面积上构筑表面结构仍然是一个非常重要的研究课题。自组装技术作为一种无模板的构筑方法,在这方面发挥了重要作用。本文着重介绍了近年来利用Langmuir-Blodgett（LB）技术在表面图案化中的应用。文中介绍了纳/微米级条带结构、岛状结构及纳米线状结构的构筑方法,其中条带结构的形成方向可以平行或垂直LB膜的转移方向。这些结构的构筑不仅可以用传统的两亲性分子,还可以用纳米粒子和纳米线等作为构筑材料。同时简单介绍了以LB技术构筑的表面纳/微米级结构在不同领域中的应用。     

表面修饰的二氧化锡纳米粒子的制备及微结构表征

采用胶体化学制得表面包覆有ＤＢＳ的二氧化锡纳米粒子，并运用一系列手段对其微结构进行了表征。     

薄层软刻蚀法制备PMMA微图案结构

对现有的软刻蚀方法提出了改进,让其与压印技术及毛细力刻蚀技术相结合形成一种薄层软刻蚀技术,并以这种技术制备出PMMA薄膜微图案化结构.在30 mm/h的拉膜速度以及弹性印章表面图形深度确定不变的情况下,PMMA流体能够完全填充到弹性印章的微通道中,SEM和光学显微镜照片证明得到的PMMA微图案是相互分离的.因此,薄层软刻蚀技术可以克服普通微模塑方法制备分离图形困难和纳米压印技术中需要使用巨大机械压力的缺点.     

水滴模板法制备聚合物蜂窝状多孔膜的研究进展

水滴模板法是一种可广泛适用于聚合物材料的动态可控的自组装模板图案化方法,利用成膜溶液溶剂挥发过程中所凝结的水滴阵列作为模板,可以实现一步法制备有序多孔膜。在经历了前期的方法学体系研究之后,对水滴模板法研究的不断深入和完善,研究的焦点已经从方法学本身逐渐转为如何将水滴模板法作为一种技术手段进行新功能和新结构的开发,并开始有了一些应用型研究的出现。本文从"基于水滴模板法的化学组分图案化研究"和"基于水滴模板法的二次结构或组分设计"两个方面来介绍水滴模板法的发展趋势与研究热点。     

巢状微结构银粒子的制备、形成机理及表面增强拉曼光谱研究

通过选择沉积电位、温度、电解液浓度等条件,调控银粒子的成核和生长速度,调控晶面的择优取向,诱导枝状生长,从而制得巢状微结构银粒子,并对其生长机理进行了研究.采用扫描电子显微镜(SEM)和X射线衍射光谱(XRD)对巢状微结构银粒子形貌和结构进行表征.以罗丹明6G为探针分子,研究了巢状微结构银粒子的表面增强拉曼光谱(SERS),并与无孔银粒子对照.结果表明:巢状微结构银粒子的SERS较无孔银粒子有明显增强,拉曼增强因子达到1.7×106.     

形状记忆聚合物表面微结构及黏附性能的可逆调控

采用模板法在形状记忆聚合物表面构筑了微纳米等级结构,获得了一种具有低黏附性的超疏水表面.在外压作用下,表面微结构发生坍塌,失去超疏水性,同时呈高黏附性.在120℃热处理后,表面微结构恢复到原始状态,同时表面恢复到低黏附状态.通过外压及热处理过程可实现对表面微结构及其黏附性能的可逆调控.研究结果表明,表面不同的微结构状态赋予了表面不同的黏附性能,即在原始表面上,液滴处于低黏附的Cassie态,而在坍塌结构表面上水滴处于高黏附的Wenzel态.     

微结构与表面修饰对二氧化硅多孔薄膜疏水性能的影响

通过引入聚乙二醇(PEG)改性传统二氧化硅(SiO2)溶胶,得到了粒径分布较宽且粒径可控的溶胶。比较了六甲基二硅氮烷(HMDS)溶胶内修饰和薄膜表面修饰以及溶胶粒径对SiO2薄膜疏水性能的影响。采用动态光散射粒度仪定量测试了二氧化硅溶胶老化过程中粒度的变化,用原子力显微镜、接触角测试仪、红外光谱仪、紫外-可见-近红外分光光度计分别对薄膜的表面形貌、表观静态接触角、薄膜成分及透光率等进行了测量。结果表明:PEG的添加可有效增大溶胶粒度从而增大薄膜的粗糙度,提高薄膜的疏水性。表面修饰效果受修饰方式和SiO2粒径影响,粒径较小时有利于溶胶内修饰,粒径较大时有利于对薄膜修饰。经过表面修饰剂(HMDS)的气氛处理得到了接触角为152°的超疏水薄膜,而且相比溶胶内修饰可以减小薄膜透光率的损失。     

水浴法制备蝴蝶状的微结构CuO

以硝酸铜为铜源,六次甲基四胺为有机碱,去离子水为溶剂,采用简捷水浴加热技术控制合成了由三角纳米片组成的蝴蝶状微结构CuO。产品的组成和形貌用XRD、EDX、场发射扫描电镜(FESEM)、TEM、HRTEM和选区电子衍射(SAED)进行了表征。结果表明CuO的形貌主要受六次甲基四胺用量的影响。随着其用量的增加,CuO的形貌经历了飞鱼状-蝴蝶状-牡丹状的递变。并对蝴蝶状CuO微结构的形成机制及形貌的演变进行了探讨。     

分子自组装法制备具有可控浸润性的铜表面

通过简单浸泡的方法在铜基底上制备出了具有微纳米复合结构的氧化铜, 再利用混合硫醇溶液[含HS(CH₂)₉CH₃和 HS(CH₂)₁₁OH]对浸泡后的表面进行修饰, 通过控制溶液中HS(CH₂)₁₁OH的浓度, 制备出一系列具有不同浸润性的铜表面, 实现表面从超疏水到超亲水的有效调控. 研究发现, 表面浸润的可控性源于表面复合结构与不同化学组成的协同作用, 微纳米复合结构的存在为表面浸润性的调节提供了必要的条件.     

具有平整表面的定向纳米碳管膜的制备

为了获得表面平整的定向纳米碳管，通过化学及物理的方法将纳米碳管膜进行反转，使其原来的AAO模板底面成为新的表面，用溶液逐步去除表面的铝和氧化铝后，获得了平整的定向纳米碳管膜表面，从而可将其作为工作面使用. 还比较了5％NaOH和6%H₃PO₄＋1.8%H₂CrO₄溶液去除氧化铝的效果.     

Fabrication of Micro‐ and Nanoscale Polymer Structures by Soft Lithography and Spin Dewetting

In this work, the process of spin dewetting of a polymer solution on a topographically patterned PDMS mold was used for fabrication of micro‐ and nanaoscale polymer structures. Spin coating was used to provide a fast and reproducible coating. This simple technique was capable of producing a wide range of polymer feature geometries from a single microfabricated mold. This experimental study looks at the effects of the original mold feature geometry as well as the polymer solution concentration on the resultant microstructures. Polystyrene and poly(propyl methacrylate) were used as model polymers. Features with film thickness ranging from <100 nm to >5 µm were obtained using this technique. The process was also extended to fabrication of nanoscale features.

     

Patterning Layered Polymeric Multilayer Films by Room‐Temperature Nanoimprint Lithography

Summary: Polyelectrolyte multilayer films of poly(acrylic acid) (PAA)/poly(allylamine hydrochloride) (PAH) and PAH/poly(sodium 4‐styrenesulfonate) (PSS) based on electrostatic interactions as a driving force are patterned by room‐temperature nanoimprint lithography (RT‐NIL). Under an imprinting pressure of 40 bar for 8 min, well‐defined pattern structures with a line width of ≈330 nm and a separation of ≈413 nm are achieved. Meanwhile, hydrogen‐bonding‐directed multilayer films of poly(vinyl pyrrolidone) (PVPON)/poly(methyl acrylic acid) (PMAA) and poly(4‐vinylpyridine)/PAA can also be patterned in a similar way by RT‐NIL. The successful imprinting of these films originates from the high compressibility and fluidity of the layered polymeric films under high pressure.

SEM image of an imprinted (PAH/PAA)*20 film on silicon wafer.     

Flexible Broadband Light Absorbers with a Superhydrophobic Surface Fabricated by Ultraviolet-assisted Nanoimprint Lithography

We present a simple approach to fabricate a kind of composite films with a superhydrophobic and broadband light absorbing surface by ultraviolet-assisted nanoimprinting over a gradiently deposited composite matrix. The wettability and optical property of the resultant surfaces are tunable by the deposition time before polymerization(T_s) and mold's topography. Mechanically robust and elastomeric films exhibiting high sunlight absorptivity up to 98.13% and contact angle of their surfaces up to 150° are prepared under optimized conditions, as using a mold with a small pattern size(hexagonal periodic mold with cylinder diameter of ca. 37 μm) under T_s=10 min for imprinting the crosslinked poly[di(ethylene glycol) ethyl ether acrylate] and poly(isobornyl acrylate) in the presence of polypyrrole(PPy) nanoparticles. Such dual functions are found related to the hierarchical architecture of the surface, arising from the synergetic effects of the periodical patterned polymer substrate and spontaneously assembled PPy microstructures on the patterns. The current strategy based on the combination of ultraviolet-assisted nanoimprint lithography and hierarchical assembly of gradiently deposited black nano-fillers offers a new insight into the design of robust superhydrophobic and black surfaces, which is helpful to deepen our understanding of the relationship between liquid/light manipulation and micro/nanostructured surfaces.     

Self-nucleation of Patterned Polymer Thin Films Defined by Soft Lithography

Chinese Journal of Polymer Science - The nucleation of crystals is often a determining step in the phase transition of materials, but it remains a challenge to control the density and specific...     

Large-Area Ordered Palladium Nanostructures by Colloidal Lithography for Hydrogen Sensing

Reliable gas sensors are very important for hydrogen (H₂) gas detection and storage. Detection methods based on palladium (Pd) metal are cost-effective and widely studied. When Pd is exposed to H₂, it turns into palladium hydride with modified optical properties, which thus can be monitored for H₂ sensing. Here, we fabricated large-area Pd nanostructures, including Pd nanotriangles and nanohole arrays, using colloidal lithography and systematically studied their H₂-sensing performance. After hydrogen absorption, both the Pd nanoholes and nanotriangles showed clear transmittance changes in the visible–near infrared range, consistent with numerical simulation results. The influences of the structural parameters (period of the array P and diameter of the nanohole D) of the two structures are further studied, as different structural parameters can affect the hydrogen detection effect of the two structures. The nanohole arrays exhibited bigger transmittance changes than the nanotriangle arrays.     

图案化TiO2薄膜的制备技术

本文综述了图案化TiO2薄膜的制备技术,按图案的生成方式可分为图案的直接生成,掩膜复制法,硬质模板复制法三大类。可以通过针尖写蚀法、电子书写蚀法、激光写蚀法、自组装法、光电化学法直接制备图案。掩膜复制法包括光刻胶法、自组装膜法、光敏凝胶膜法等。硬质模板法也称软刻蚀技术,分为复制微模塑、转移微模塑、毛细管微模塑、微接触印刷法、光-盖印印刷等技术。对每类方法的优缺点作了适当评述,对今后图案化TiO2薄膜制备的研究方向提出了一些建议。     

Fabrication of fluorescent surface relief patterns using AIE polymer through a soft lithographic approach

A new aggregation‐induced emission (AIE) active polymer (PS‐TPE) with high tetraphenylethene (TPE) loading density was synthesized. The synthesized polymer showed significant AIE properties, good solubility and high thermal stability. Soft‐lithographic contact printing process by using photoinduced surface relief structures on azo polymer film as masters and duplicated PDMS elastomer as stamps was used to fabricate fluorescent PS‐TPE patterns. Various fluorescent structures with high contrast including surface relief gratings, periodically dotted patterns, and quasi‐crystal structures can be easily fabricated through this approach. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1838–1845     

Emergent Soft Lithographic Tools for the Fabrication of Functional Polymeric Microstructures

Polymeric microstructures (PMs) are useful to a broad range of technologies applicable to, for example, sensing, energy storage, and soft robotics. Due to the diverse application space of PMs, many techniques (e. g., photolithography, 3D printing, micromilling, etc.) have been developed to fabricate these structures. Stemming from their generality and unique capabilities, the tools encompassed by soft lithography (e. g., replica molding, microcontact printing, etc.), which use soft elastomeric materials as masters in the fabrication of PMs, are particularly relevant. By taking advantage of the characteristics of elastomeric masters, particularly their mechanical and chemical properties, soft lithography has enabled the use of non-planar substrates and relatively inexpensive equipment in the generation of many types of PMs, redefining existing communities and creating new ones. Traditionally, these elastomeric masters have been produced from relief patterns fabricated using photolithography; however, recent efforts have led to the emergence of new methods that make use of masters that are self-forming, dynamic in their geometric and chemical properties, 3D in architecture, and/or sacrificial (i. e., easily removed/released using phase changes). These “next generation” soft lithographic masters include self-assembled liquid droplets, microscale balloons, templates derived from natural materials, and hierarchically microstructured surfaces. The new methods of fabrication supported by these unique masters enable access to numerous varieties of PMs (e. g., those with hierarchical microstructures, overhanging features, and 3D architectures) that would not be possible following established methods of soft lithography. This review explores these emergent soft lithographic methods, addressing their operational principles and the application space they can impact.     

高多孔度多孔硅自支撑膜的制备与表征

发光多孔硅由于在光电子学方面的应用前景而引起人们极大的关注[1]．最近多孔硅发光二极管的研究方面取得了重大进展[2]。但是，有关多孔硅的发光机制仍然存在着争论[1，3，4]，利由于消除了单晶硅衬底的影响，对脱离了硅衬底的多孔硅自支撑膜能够进行普通多孔硅所不能进行的一