胶体阵列及三维光子晶体制备的研究进展

单分散的胶体颗粒能自发排列成胶体阵列,其长程有序结构能获得许多特殊的性质.胶体阵列被用作制备可见光及近红外波长范围的光子晶体的基础.以其为模板制备的反蛋白石结构可拥有全光子禁带,为新一代光子器件开发和应用带来了希望.介绍了单分散胶体颗粒的主流制备方法,归纳总结了胶体阵列制备的几种方法和国内外最新的相关报道,简述了其在制备三维光子晶体领域的最新进展以及该领域国内外的研究进展.     

多彩结构色‒柔性光子晶体材料与应用

目的 对柔性光子晶体的性质进行介绍,并对其主流的制备方法进行阐述,总结近几年来柔性光子晶体材料在包装印刷领域的应用。方法 介绍柔性光子晶体材料的主流制备方法,包括胶体粒子自组装法以及纳米压印光刻法;其次根据光子晶体材料的结构色可调性,介绍柔性光子晶体材料在包装印刷领域主要应用和研究价值。结论 目前柔性光子晶体在包装印刷方面的应用主要在于纺织、防伪、体育与健康等方面。柔性光子晶体在绿色印刷和包装领域具有重大潜力,可进一步深度研究拓宽其日常生活领域化应用,进一步推动包装印刷行业的绿色发展。     

光子晶体用二氧化硅胶体球的改性制备及其自组装

采用一步法制备了表面接枝甲基丙烯酰氧基三甲氧基硅烷(MPS)的单分散SiO2胶体球,并通过垂直沉积法在40℃、60%相对湿度下组装出有序性较好的密排结构的SiO2光子晶体.傅立叶红外光谱(FT-IR)和X射线光电子能谱(XPS)结果证明SiO2胶体球表面接枝上了MPS;扫描电子显微镜(SEM)结果表明改性后SiO2胶体球平均粒径为284nm,单分散性较高,平均标准偏差＜5%;制备出的光子晶体是面心立方(fcc)紧密堆积结构;吸收光谱表明,所制备的光子晶体在(111)方向具有光子晶体的带隙特性,带隙中心波长为646nm.     

二氧化硅胶体晶体的制备及其光子带隙特性

利用胶体颗粒悬浊液的自组织生长技术制备了两种二氧化硅胶体晶体．透射光谱表明：所制备的胶体晶体的光子带隙位于近红外波段,带隙的位置随胶体晶体中胶粒的尺寸而变化;且放置时间延长,带隙将发生蓝移．     

复合结构光子晶体的制备及应用

复合结构纳米粒子具有许多不同于单组分胶体粒子的独特的光、电、磁、催化等物理与化学性质,是构筑光子晶体材料的重要组元.从材料复合的不同形式阐述了复合结构光子晶体的制备方法;列举了光子晶体器件的典型应用.综述了光子晶体的主要用途;并展望了复合结构光子晶体的发展方向.     

光子晶体的研究进展

从20世纪80年代末提出光子晶体的概念以来,由于光子晶体独特的调节光子运动状态的特性,使其在许多领域有着广泛的用途.系统叙述了光子晶体的产生、结构、制备和应用,介绍了ZnO光子晶体的最新研究进展.     

聚苯乙烯微球的制备及其在光子晶体中的应用

亚微米级聚苯乙烯微球是一类常见的制备光子晶体的材料。综述了分散聚合法和乳液聚合法制备光子晶体用单分散聚苯乙烯微球的研究进展;介绍了聚苯乙烯胶体球在蛋白石结构、反蛋白石结构和可调制光子晶体中的应用进展;并提出了今后的研究方向。     

光子晶体的研究进展

从20世纪80年代末提出光子晶体的概念以来,由于光子晶体独特的调节光子运动状态的特性,使其在许多领域有着广泛的用途.系统叙述了光子晶体的产生、结构、制备和应用,介绍了ZnO光子晶体的最新研究进展.     

CdSe-SiO2光子晶体的垂直沉积及近红外变频特性

在氧化铟锡玻璃上电化学合成了CdSe薄膜,采用垂直沉积法首次在CdSe薄膜上制备了SiO2胶体晶体, 实现了CdSe表面介电常数的调节.扫描电镜观察表明,500nm微球在CdSe薄膜上呈面心立方密堆结构排列,在微米尺度上胶体晶体显示出一定的多晶序.与SiO2胶体晶体相比,CdSe-SiO2光子晶体的UV-vis-NIR透射谱只有一个较宽的光子带隙,带隙在近红外波段随入射角减小向短波方向移动.所得CdSe-SiO2光子晶体样品可作为地面目标针对红外卫星成像的伪装材料.     

二维胶体晶体成形及应用研究进展

综述了二维胶体晶体的结构特点及成形驱动力,介绍了LB(Langmuir-Blodgett)转移法、毛细组装法、电场沉积组装法、特殊装置组装法等二维胶体晶体成形方法的原理、成形过程及优缺点,同时概述了二维胶体晶体在微加工及微图案化、纳米传感器、纳米磁存储等领域的应用情况。     

Nanoparticle assembly into a patterned template by controlling the surface wettability

This study demonstrates a straightforward route for an assembly of colloidal nanoparticles into a desired area in a patterned template, using an evaporation method. An alternative method for fabricating a nanometer-scaled patterned template for the assembly of colloidal nanoparticles and different phenomena of colloidal nanoparticle template assemblies according to the surface wettability are presented. We also suggest that an adequate combination of the surface wettability coupled with the physical confinement afforded by the template should allow colloidal nanoparticle assembly into templates with various patterns.     

Instantaneous,Simple, and Reversible Revealing of Invisible Patterns Encrypted in Robust Hollow Sphere Colloidal Photonic Crystals

The colors of photonic crystals are based on their periodic crystalline structure. They show clear advantages over conventional chromophores for many applications, mainly due to their anti‐photobleaching and responsiveness to stimuli. More specifically, combining colloidal photonic crystals and invisible patterns is important in steganography and watermarking for anticounterfeiting applications. Here a convenient way to imprint robust invisible patterns in colloidal crystals of hollow silica spheres is presented. While these patterns remain invisible under static environmental humidity, even up to near 100% relative humidity, they are unveiled immediately (≈100 ms) and fully reversibly by dynamic humid flow, e.g., human breath. They reveal themselves due to the extreme wettability of the patterned (etched) regions, as confirmed by contact angle measurements. The liquid surface tension threshold to induce wetting (revealing the imprinted invisible images) is evaluated by thermodynamic predictions and subsequently verified by exposure to various vapors with different surface tension. The color of the patterned regions is furthermore independently tuned by vapors with different refractive indices. Such a system can play a key role in applications such as anticounterfeiting, identification, and vapor sensing.     

Grafted polymeric nanostructures patterned bottom-up by colloidal lithography and initiated chemical vapor deposition (iCVD)

Colloidal lithography is a popular non-conventional process which uses two-dimensional self-assembled monolayer arrays of colloidal nanoparticles as masks for “top-down” techniques such as etching or sputtering. Initiated Chemical Vapor Deposition (iCVD) is a surface controlled process which offers unprecedented opportunity for producing polymer brushes patterned through a colloidal template by grafting to substrates with dangling vinyl bonds. We demonstrate a generic “bottom-up” process as an inexpensive and simple technique for creating well-ordered arrays of functional patterned polymeric nanostructures. These patterns were produced from p(butyl acrylate) and p(hydroxyethyl methacrylate), and are robustly tethered to the underlying substrate as demonstrated by their ability to withstand aggressive solvent.     

Patterning hierarchy in direct and inverse opal crystals

Biological strategies for bottom-up synthesis of inorganic crystalline and amorphous materials within topographic templates have recently become an attractive approach for fabricating complex synthetic structures. Inspired by these strategies, herein the synthesis of multi-layered, hierarchical inverse colloidal crystal films formed directly on topographically patterned substrates via evaporative deposition, or "co-assembly", of polymeric spheres with a silicate sol-gel precursor solution and subsequent removal of the colloidal template, is described. The response of this growing composite colloid-silica system to artificially imposed 3D spatial constraints of various geometries is systematically studied, and compared with that of direct colloidal crystal assembly on the same template. Substrates designed with arrays of rectangular, triangular, and hexagonal prisms and cylinders are shown to control crystallographic domain nucleation and orientation of the direct and inverse opals. With this bottom-up topographical approach, it is demonstrated that the system can be manipulated to either form large patterned single crystals, or crystals with a fine-tuned extent of disorder, and to nucleate distinct colloidal domains of a defined size, location, and orientation in a wide range of length-scales. The resulting ordered, quasi-ordered, and disordered colloidal crystal films show distinct optical properties. Therefore, this method provides a means of controlling bottom-up synthesis of complex, hierarchical direct and inverse opal structures designed for altering optical properties and increased functionality.     

Inverse Opal Scaffolds with an Embossed Surface Pattern Prepared from Sticky Golf‐Ball‐Shaped Microparticle Assemblies

Inverse opal scaffolds presenting an embossed‐pattern surface are prepared from colloidal crystal assemblies of uniformly sized golf‐ball‐shaped microparticles. Post‐treatments, such as thermal annealing during the bridging of the microparticles for opal preparation, are avoided to prevent deterioration of surface patterns of the sacrificial template. This presents a new approach to increase the surface‐area‐to‐volume ratio (SAV) by the alteration of morphological features in sophisticated 3D structures that remain largely unexamined owing to difficulties in their preparation. Previous results observed in 2D surfaces that show effective performance improvement through an increase in contact area, especially in biomedical applications, also appear applicable to patterned inverse opal scaffolds based on comparable results obtained from cell cultures. As the field of application of opal and inverse opal structures is expanding due to their unique structural advantages, such as 3D interconnectivity and periodic structures, our strategy opens the door for the use of patterned surfaces on highly sophisticated 3D structures, improving their performance via an increase in SAV.     

Interfacial Capillary‐Force‐Driven Self‐Assembly of Monolayer Colloidal Crystals for Supersensitive Plasmonic Sensors

Colloidal lithography technology based on monolayer colloidal crystals (MCCs) is considered as an outstanding candidate for fabricating large‐area patterned functional nanostructures and devices. Although many efforts have been devoted to achieve various novel applicatons, the quality of MCCs, a key factor for the controllability and reproducibility of the patterned nanostructures, is often overlooked. In this work, an interfacial capillary‐force‐driven self‐assembly strategy (ICFDS) is designed to realize a high‐quality and highly‐ordered hexagonal monolayer MCCs array by resorting the capillary effect of the interfacial water film at substrate surface as well as controlling the zeta potential of the polystyrene particles. Compared with the conventional self‐assembly method, this approach can realize the reself‐assembly process on the substrate surface with few colloidal aggregates, vacancy, and crystal boundary defects. Furthermore, various typical large‐scale nanostructure arrays are achieved by combining reactive ion etching, metal‐assisted chemical etching, and so forth. Specifically, benefiting from the as‐fabricated high‐quality 2D hexagonal colloidal crystals, the surface plasmon resonance (SPR) sensors achieve an excellent refractive index sensitivity value of 3497 nm RIU^?1, which is competent for detecting bovine serum albumin with an ultralow concentration of 10^?8 m . This work opens a window to prepare high‐quality MCCs for more potential applications.     

Enhanced adhesion of bioinspired nanopatterned elastomers via colloidal surface assembly

We describe a scalable method to fabricate nanopatterned bioinspired dry adhesives using colloidal lithography. Close-packed monolayers of polystyrene particles were formed at the air/water interface, on which polydimethylsiloxane (PDMS) was applied. The order of the colloidal monolayer and the immersion depth of the particles were tuned by altering the pH and ionic strength of the water. Initially, PDMS completely wetted the air/water interface outside the monolayer, thereby compressing the monolayer as in a Langmuir trough; further application of PDMS subsequently covered the colloidal monolayers. PDMS curing and particle extraction resulted in elastomers patterned with nanodimples. Adhesion and friction of these nanopatterned surfaces with varying dimple depth were studied using a spherical probe as a counter-surface. Compared with smooth surfaces, adhesion of nanopatterned surfaces was enhanced, which is attributed to an energy-dissipating mechanism during pull-off. All nanopatterned surfaces showed a significant decrease in friction compared with smooth surfaces.     

Patterning Porous Oxides within Microchannel Networks

A continuing challenge for materials chemists and engineers is the ability to create multifunctional composite structures with well‐defined superimposed structural order from nanometer to micrometer length scales. Materials with three‐dimensional structures ordered over multiple length scales can be prepared by carrying out colloidal crystallization and inorganic/organic cooperative self‐assembly within microchannel networks. The resulting materials show hierarchical ordering over several discrete and tunable length scales ranging from several nanometers to micrometers. These patterned porous materials hold promise for use as advanced catalysts, sensors, low‐k dielectrics, optoelectronic and integrated photonic crystal devices.     

Optimized film processing of nanosilver colloids for photoluminescence enhancement

Recently, various research strategies have been employed to improve light extraction efficiency in organic LEDs, including the recent development of localized surface plasmon resonance (LSPR), as well as the more widely-known application of a photonic crystal layer. Here, we report on the development of a process method for forming a two-dimensional nanosilver patterned array to achieve LSPR-coupled light-emission efficiency enhancement. The process scheme involves the spin-coating of nanosilver colloidal ink onto a glass substrate, followed by optimized thermal annealing to create an array of isolated nanosilver islands. The resulting Ag islands are in the size range 50 approximately 80 nm, which is larger than the diameter of the Ag nanoparticles in the colloidal suspension. Then, silicon oxide is thermally sputtered to provide a spacer layer to prevent luminescence quenching of the red-emitting nanocrystal quantum dot (NQD) layer, which is deposited in a subsequent spin-coating process. When the NQD layer is excited, the energy of the photoelectron is confined to the surfaces of the nanosilver islands in the near-field. In this study, the localized surface plasmon resonance peaks were at a wavelength of 625 nm, and out-coupling efficiency was enhanced more than sixfold.     

Effect of the phosphorous-containing ligands on synthesis and properties of GaSe nanoparticles

We discuss the effect of the alkylphosphonic species on synthesis processes as well as structural and optical properties of colloidal GaSe nanoparticles. Ligand-capping models of the above-mentioned nanoparticles and their advantages are proposed. An improvement of conventional metalorganic syntheses was implemented. It lies within the controlled addition of octadecylphosphonic anhydride to metal precursor in order to serve both as inhibitor of fast nucleation as well as capping and passivating ligands for the GaSe colloidal nanoparticles.