Optical properties of three-dimensional P(St-MAA) photonic crystals on polyester fabrics

The three-dimensional (3D) photonic crystals with face-centered cubic (fcc) structure was fabricated on polyester fabrics, a kind of soft textile materials quite different from the conventional solid substrates, by gravitational sedimentation self-assembly of monodisperse P(St-MAA) colloidal microspheres. The optical properties of structural colors on polyester fabrics were investigated and the position of photonic band gap was characterized. The results showed that the color-tuning ways of the structural colors from photonic crystals were in accordance with Bragg’s law and could be modulated by the size of P(St-MAA) colloidal microspheres and the viewing angles. The L¹a¹b¹ values of the structural colors generated from the assembled polyester fabrics were in agreement with their reflectance spectra. The photonic band gap position of photonic crystals on polyester fabrics could be consistently confirmed by reflectance and transmittance spectra.     

Large‐Scale Noniridescent Structural Color Printing Enabled by Infiltration‐Driven Nonequilibrium Colloidal Assembly

Structural colors originating from interaction of light with intricately arranged micro‐/nanostructures have stimulated considerable interest because of their inherent photostability and energy efficiency. In particular, noniridescent structural color with wide viewing angle has been receiving increasing attention recently. However, no method is yet available for rapid and large‐scale fabrication of full‐spectrum structural color patterns with wide viewing angles. Here, infiltration‐driven nonequilibrium assembly of colloidal particles on liquid‐permeable and particle‐excluding substrates is demonstrated to direct the particles to form amorphous colloidal arrays (ACAs) within milliseconds. The infiltration‐assisted (IFAST) colloidal assembly opens new possibilities for rapid manufacture of noniridescent structural colors of ACAs and straightforward structural color mixing. Full‐spectrum noniridescent structural colors are successfully produced by mixing primary structural colors of red, blue, and yellow using a commercial office inkjet printer. Rapid fabrication of large‐scale structural color patterns with sophisticated color combination/layout by IFAST printing is realized. The IFAST technology is versatile for developing structural color patterns with wide viewing angles, as colloidal particles, inks, and substrates are flexibly designable for diverse applications.     

Inkjet Printing of Patterned,Multispectral, and Biocompatible Photonic Crystals

Patterning of photonic crystals to generate rationally designed color‐responsive materials has drawn considerable interest because of promising applications in optical storage, encryption, display, and sensing. Here, an inkjet‐printing based strategy is presented for noncontact, rapid, and direct approaches to generate arbitrarily patterned photonic crystals. The strategy is based on the use of water‐soluble biopolymer‐based opal structures that can be reformed with high resolution through precise deposition of fluids on the photonic crystal lattice. The resulting digitally designed photonic lattice formats simultaneously exploit structural color and material transience opening avenues for information encoding and combining functions of optics, biomaterials, and environmental interfaces in a single device.     

Characterization of inks and ink application for ink-jet printing: model and simulation

Ink-jet printing quality is determined primarily by, among other factors, the printing engine and its inks. The printing engine controls the process of ink application and the scheme of ink mixing for th e generation of secondary and tertiary colors. The inks selectively absorb different wavelengths from the illumination and result in the visible color output. Therefore characterizations of the output print in terms of ink distribution and volume, the scheme of ink mixing, light absorption, and light scattering are of essential importance in controlling and understanding the quality of the color reproduction. I present a method to characterize the ink volume and the properties of the ink by means of spectral reflectance measurements and simulations. The simulations are based on the Kubelka-Munk theory, whose applicability to ink-jet printing is also discussed.     

喷墨印刷技术研究现状与发展对策

目的通过研究印刷技术的原理、产生和发展,为喷墨印刷技术的应用开拓研究思路。方法通过研究喷墨印刷技术原理和国内外研究现状,分析我国现有喷墨印刷技术发展中存在的问题,总结该项技术在研究应用中关键技术问题,并提出未来研究的主要发展方向和对策。结论现阶段研究应主要着力于以下5个方面,喷墨印刷系统本体研究,尤其是集成数字化喷墨复合设备的研发;加大突破喷头研发攻关,研发出适用性好且有独立知识产权的高速、低成本喷头;在提高墨滴喷射精度的同时,提升控制系统的集成度和适用性;针对不同油墨,积极研发适用性强的智能供墨系统,实时为喷头腔体提供理想墨流环境;加强和培养复合型人才。     

Nano-sized ceramic inks for drop-on-demand ink-jet printing in quadrichromy

Nano-sized ceramic inks suitable for ink-jet printing have been developed for the four-colours CMYK (cyan, magenta, yellow, black) process. Nano-inks of different pigment composition (Co(1-x)O, Au(0), Ti(1-x-y)Sb(x)Cr(y)O2, CoFe2O4) have been prepared with various solid loadings and their chemicophysical properties (particle size, viscosity, surface tension, zeta-potential) were tailored for the ink-jet application. The pigment particle size is in the 20-80 nm range. All these nano-suspensions are stable for long time (i.e., several months) due to either electrostatic (high zeta-potential values) or steric stabilization mechanisms. Both nanometric size and high stability avoid problems of nozzle clogging from particles agglomeration and settling. Nano-inks have a Newtonian behaviour with relatively low viscosities at room temperature. More concentrated inks fulfil the viscosity requirement of ink-jet applications (i.e., < 35 mPa x s) for printing temperatures in between 30 and 70 degrees C. Surface tension constraints for ink-jet printing are fulfilled by nano-inks, being in the 35-45 mN x m(-1) range. The nano-sized inks investigated behave satisfactorily in preliminary printing tests on several unfired industrial ceramic tiles, developing saturated colours in a wide range of firing temperatures (1000-1200 degrees C).     

数码喷绘质量影响因素分析

本文在介绍了喷绘原理与技术特点的基础上,探讨了环境因素、图像前处理、设备关键单元、油墨、承印介质及两者之间的成像适性对喷绘质量的影响,并提出相关的改进措施。从分析结果来看,要获得好的喷绘质量,在设备条件一定的情况下,其中喷墨墨水和承印介质良好的匹配性最为关键,同时兼顾其它各因素及因素之间对喷绘质量的影响。     

Nanoscale patterning of colloidal quantum dots on transparent and metallic planar surfaces

The patterning of colloidal quantum dots with nanometer resolution is essential for their application in photonics and plasmonics. Several patterning approaches, such as the use of polymer composites, molecular lock-and-key methods, inkjet printing and microcontact printing of quantum dots have been recently developed. Herein, we present a simple method of patterning colloidal quantum dots for photonic nanostructures such as straight lines, rings and dot patterns either on transparent or metallic substrates. Sub-10?nm width of the patterned line could be achieved with a well-defined sidewall profile. Using this method, we demonstrate a surface plasmon launcher from a quantum dot cluster in the visible spectrum.     

基于胶体微球自组装光子晶体的结构生色

综述了近年来基于胶体微球自组装光子晶体结构生色的研究进展。先简要介绍了光子晶体和结构生色理论,然后阐述了以胶体微球为基本结构基元构筑光子晶体的自组装方法,探讨了光子晶体的结构色效果的表征方式和稳固性增强方法,最后总结了用胶体微球自组装法制备光子晶体的困难并展望了发展方向。     

Tunable Photonic Microspheres of Comb‐Like Supramolecules

Photonic crystals (PCs) are ideal candidates for reflective color pigments with high color purity and brightness due to tunable optical stop band. Herein, the generation of PC microspheres through 3D confined supramolecular assembly of block copolymers (polystyrene‐block‐poly(2‐vinylpyridine), PS‐b‐P2VP) and small molecules (3‐n‐pentadecylphenol, PDP) in emulsion droplets is demonstrated. The intrinsic structural colors of the PC microspheres are effectively regulated by tuning hydrogen‐bonding interaction between P2VP blocks and PDP, where reflected color can be readily tuned across the whole visible spectrum range. Also, the effects of both PDP and homopolymer (hPS) on periodic structure and optical properties of the microspheres are investigated. Moreover, the spectral results of finite element method (FEM) simulation agree well with the variation of structural colors by tuning the periodicity in PC microspheres. The supramolecular microspheres with tunable intrinsic structural color can be potentially useful in the various practical applications including display, anti‐counterfeit printing and painting.     

喷墨CTP技术及应用

本文简要介绍了喷墨CTP技术的发展，特点及制版工艺，并重点介绍了裸版喷墨CTP的制版方法及评价方法，还介绍了喷墨打印机系统及墨水的开发状况。     

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.     

基于喷墨印刷的OTFT的制备与性能研究

介绍了喷墨印刷技术和OTFT的结构,通过建立几个模型,分别模拟了喷墨印刷过程中聚合物油墨的粘度和喷墨印刷过程中的瞬间油墨液滴的状态,以及印制成型后OTFT基本的性能.通过模型模拟来展示在用喷墨的方法来印制OTFT的过程中需要注意的问题,并且作出了对印制好的OTFT的性能的测定指标.     

Direct printing of silver nanoparticles by an agarose stamp on planar and patterned substrates

In this study, we have used an agarose stamp to conduct direct printing of silver nanoparticles, nanowires and nanoplates on both planar and structured substrates. Nanoparticle solution could be first coated on an agarose stamp, and then transferred to a planar substrate. Micro-patterns comprising metal nanoparticles could be printed on planar substrates without the formation of residual layers. Thus a three-dimensional metal microstructure could be easily fabricated. The patterning of electrodes by printing Ag nanowires directly on TiO(2) was also demonstrated to fabricate resistive random access memory (RRAM) devices by all-solution-processing methods. By using a flat agarose stamp, the patterns printed on the microstructured substrates were quite different from those on the nanostructured substrates. On the microstructured substrates, direct printing could print silver nanoparticles onto the protrusion surface, and could print silver layers as thick as several microns, useful for high conductivity electrodes. On the substrates with nanostructures such as photonic crystals or nano-gratings, direct printing could transfer nanoparticles into the grooves or cavities only due to the contact of the agarose stamp with the groove or concavity surface. A new approach to fabricate metal wire grid polarizers was further demonstrated. A nanoporous agarose stamp has a good potential for printing using nanoparticle suspension.     

Colloidal particles with various glass transition temperatures: preparation, assembly, and the properties of stop bands under heat treatment

Monodisperse P(St-co-nBA-co-AA) colloidal microspheres with various glass transition temperatures (T _gs), whose average particle sizes were about 300 nm, were prepared using soap-free emulsion polymerization by adjusting the ratio of styrene and n-butyl acrylate. Colloidal photonic crystals were assembled with these microspheres by vertical deposition method. Stop bands of colloidal crystals under different temperatures have been characterized. The relationship between the stop band and temperature was indicated. The microstructure and reflectance spectra of photonic crystals were characterized by SEM and fiber spectrometer, respectively. Results showed that as the temperature increased, only a little red shift of stop band appeared in the vicinity of T _g and the intensity of the maximum reflection peak decreased until the stop bands disappeared. Furthermore, enough heating time at the T _g ±2 °C could also lead to the disappearance of stop bands. What’s more, colloidal crystal films with certain connection strength were obtained by simple heating.     

Position- and Orientation-Controlled Growth of Wulff-Shaped Colloidal Crystals Engineered with DNA

Colloidal crystals have emerged as promising candidates for building optical microdevices. Techniques now exist for synthesizing them with control over their nanoscale features (e.g., particle compositions, sizes, shapes, and lattice parameters and symmetry); however, the ability to tune macroscale structural features, such as the relative positions of crystals to one another and lattice orientations, has yet to be realized. Here, inspiration is drawn from epitaxial growth strategies in atomic crystallization, and patterned substrates are prepared that, when used in conjunction with DNA-mediated nanoparticle crystallization, allow for control over individual Wulff-shaped crystal growth, location, and orientation. In addition, the approach allows exquisite control over the patterned substrate/crystal lattice mismatch, something not yet realized for any epitaxy process. This level of structural control is a significant step toward realizing complex, integrated devices with colloidal crystal components, and this approach provides a model system for further exploration in epitaxy systems.     

高性能水性上转换荧光油墨的制备及包装防伪应用

将一步合成法制备的氨基修饰类沸石咪唑酯骨架晶体原位引入水性聚氨酯(WPU)基体中,结合酮肼交联改性,制备室温自交联WPU分散液.以水热法合成的稀土掺杂NaYF4上转换晶体为颜料、改性WPU分散液为连接料,制备水性上转换荧光油墨,并探讨其在包装防伪中的应用.结果表明:综合改性WPU涂膜的抗水性能和热稳定性明显提高,三基色油墨具备良好的印刷适性和稳定性;印制的防伪标签,自然光下不可见,在980 nm激光照射下呈现出精细的多色荧光团花图案.基于高性能水性上转换荧光油墨,结合印刷工艺防伪技术实现综合防伪,为绿色高端包装防伪提供了新的思路.     

Synthesis of green emitting and transparent zn2siO4:mn2+ thin film phosphors on 2D photonic crystal patterned quartz substrates

Zn2SiO4:Mn2+ thin film phosphors (TFPs) have been synthesized by RF magnetron sputtering, using a single multicomponent stoichiometric target. And 2D photonic crystal patterns were introduced on a quartz substrate to enhance the light extraction efficiency. In order to introduce 2D photonic crystal patterns on a quartz substrate, nanosphere lithography was used. Polystyrene spheres, with diameter of 330 nm, were transferred on the quartz substrate and subsequently were served as an etch mask. Quartz substrates were patterned by CF4 gas-based reactive ion etching. Zn2SiO4:Mn2+ were deposited on that 2D photonic crystal patterned quartz substrate and the effect of height of photonic crystal layers were investigated. The light extraction efficiency of Zn2SiO4:Mn2+ thin film phosphors deposited on the photonic crystal patterned quartz substrate was enhanced three times to compared with that of flat Zn2SiO4:Mn2+ thin film phosphors due to the Bragg diffraction and leaky mode caused by PCLs. Transmittance of Zn2SiO4:Mn2+ TFPs deposited on the photonic crystal patterned substrate was high enough, above 70% in the visible light region with respect to that of quartz substrate.     

机械力致变色光子晶体材料研究进展

目的 总结光子晶体材料在机械力致变色方面的研究现状,基于机械力致变色光子晶体的特点进行展望,为进一步研究和应用提供参考.方法 基于机械力的施加方式,从拉伸变色和压缩变色两个方面系统介绍了机械力致变色光子晶体的制备方法、光学性能以及机械性能,并分析比较了这两种光子晶体材料的应用现状和前景.结论 机械力致变色光子晶体在结构上有多种形式,包括嵌入胶体阵列的弹性体光子晶体、胶体交联光子晶体、层状光子晶体、链状光子晶体等,近些年这些光子晶体已经可以达到明亮的结构色和应变能力.机械力致变色光子晶体因其形式的多样性和良好的光学、机械性能,使其在应力检测、人体运动状态监测、防伪、显示等方面得以应用,具有很大的实际应用潜力.     

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。