共查询到20条相似文献，搜索用时 0 毫秒
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Ye Hun Choi;Jiwoo Lee;Esther Amstad;Shin-Hyun Kim; 《Small (Weinheim an der Bergstrasse, Germany)》2024,20(20):2309512
Colloids self-organize into icosahedral clusters composed of a Mackay core and an anti-Mackay shell under spherical confinement to minimize the free energy. This study explores the variation of surface arrangements of colloids in icosahedral clusters, focusing on the determining factors behind the surface arrangement. To efficiently assemble particles in emulsion droplets, droplet-to-droplet osmotic extraction from particle-laden droplets to salt-containing droplets is used, where the droplets are microfluidically prepared to guarantee a high size uniformity. The icosahedral clusters are optimally produced during a 24-h consolidation period at a 0.04 m salt concentration. The findings reveal an increase in the number of particle layers from 10 to 15 in the icosahedral clusters as the average number of particles increases from 3300 to 11 000. Intriguingly, the number of layers in the anti-Mackay shells, or surface termination, appears to more strongly depend on the sphericity of the clusters than on the deviation in the particle count from an ideal icosahedral cluster. This result suggests that the sphericity of the outermost layer, formed by the late-stage rearrangement of particles to form an anti-Mackay shell near the droplet interface, may play a pivotal role in determining the surface morphology to accommodate a spherical interface. 相似文献
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Carina Bittner;Gudrun Bleyer;Nico Nees;Miguel Carneiro;Lukas Pflug;Michael Stingl;Nicolas Vogel; 《Advanced Materials Interfaces》2024,11(12):2300986
Nanostructured materials that mimic structural coloration in nature can be synthetically created by colloidal self-assembly. To maximize optical effects, the natural world integrates melanin as a broadband absorber to remove incoherently scattered light. Polydopamine (PDA) is used as a synthetic analog of natural melanin to systematically investigate the influence of absorber quantity and distribution on color saturation in colloidal photonic crystals. The absorbing PDA is integrated into two distinct ways: homogenous colloidal crystals are produced from core–shell particles with incrementally increasing polydopamine shells, and heterogeneous colloidal crystals are formed by co-assembly of varying ratios of polystyrene (PS) and absorbing PS@PDA particles. The chromaticity is quantified by converting the measured spectra to reconstructed colors in the L*a*b* color sphere to identify structures with optimal color saturation. Simulations based on the discrete dipole approximation (DDA) indicate that a homogeneous absorber distribution is most efficient in creating saturated structural coloration. Experiments, however, demonstrate that the heterogeneous absorber incorporation outperforms the homogeneous strategies, as it allows for a more precise adjustment of the absorber content in the required concentration range. These results underline the importance of incorporating absorbers and indicate efficient ways in which colloidal photonic crystals with saturated structural colors can be prepared. 相似文献
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Inspired by the actuator mechanism of Venus flytrap leaves, presented is a bilayer structural color hydrogel actuator by employing a hybrid inverse opal scaffold to join the poly(acrylic acid‐co‐acrylamide) layer and the poly(N‐isopropylacrylamide) layer together. The nanostructure of the inverse opal scaffold imparts the bilayer hydrogel with brilliant structural color, which can show a reversible coloration switch during the structural change. An internal water distribution occurs in the composite bilayer hydrogel during the heating or cooling process because of the opposite thermo‐responsiveness of the two hydrogels. Thus, this intelligent soft material can work in various environments and break the limitation of aqueous media of most structural color hydrogels. In addition, the water transference of the bilayer hydrogel enables the material with bending/unbending deformations and hence a series of complex motions like screwing, catching, and releasing can be achieved. Attractively, with the integrating of graphene oxide, the hydrogel systems can even be imparted with near‐infrared remote responsiveness to both of their color change and 3D deformation. These features of the bioinspired bilayer structural color hydrogel indicate its potential values in a variety of intelligent soft material applications. 相似文献
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Takahiro Yamanaka;Naoki Tarutani;Kiyofumi Katagiri;Kei Inumaru;Yukikazu Takeoka; 《Advanced Engineering Materials》2024,26(14):2400814
This article highlights the critical factors influencing the mechanical robustness of structurally colored coatings formed as arrays of monodisperse SiO2 particles. Various types of coatings can be fabricated using electrophoretic deposition (EPD) techniques. Anodic EPD generates coatings with colloidal crystalline structures, iridescent structural color, and noteworthy mechanical robustness owing to interparticle necking during heat treatment, even in the absence of binder additives. Conversely, coatings prepared via cathodic EPD exhibit noniridescent structural color and colloidal amorphous structure, with only marginally improved mechanical robustness after high-temperature treatment. However, when Mg(OH)2 is codeposited during EPD in the coating, the resultant film exhibits strong adhesion between particles and the substrate—as evidenced by minimal peeling from the substrate even after ultrasonication for 6 h—owing to the binding effect of MgO, which is converted from Mg(OH)2 via heat treatment. The robustness of the film is not dictated by the size of the SiO2 particles, suggesting that this approach can be applied to structurally colored coatings of various colors. Consequently, the results suggest that EPD with the addition of a binder and heat treatment can be used to fabricate particle-array-type coatings with extremely high mechanical robustness. 相似文献
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Gun Ho Lee Jong Bin Kim Tae Min Choi Jung Min Lee Shin‐Hyun Kim 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(5)
Colloidal crystals and glasses have their own photonic effects. Colloidal crystals show high reflectivity at narrowband, whereas colloidal glasses show low reflectivity at broadband. To compromise the opposite optical properties, a simple means is suggested to control the colloidal arrangement between crystal and glass by employing two different sizes of silica particles with repulsive interparticle potential. Monodisperse silica particles with repulsive potential spontaneously form crystalline structure at volume fraction far below 0.74. When two different sizes of silica particles coexist, the arrangement of silica particles is significantly influenced by two parameters: size contrast and mixing ratio. When the size contrast is small, a long‐range order is partially conserved in the entire mixing ratio, resulting in a pronounced reflectance peak and brilliant structural color. When the size contrast is large, the long‐range order is rapidly reduced along with mixing ratio. Nevertheless, a short‐range order survives, which causes low reflectivity at a broad wavelength, developing faint structural colors. These findings offer an insight into controlling the colloidal arrangements and provide a simple way to tune the optical property of colloidal arrays for structural coloration. 相似文献
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Jae Young Sim Gun Ho Lee Shin‐Hyun Kim 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(37):4938-4945
Colloidal photonic structures have been designed to have granular format to use them for paint pigments, encoded carriers, and display pixels. However, conventional approaches only provide spherical or discoid shapes, restricting their applications. Cylindrical granules with fan‐shaped compartments in the cross section are appealing for microcarriers with abundant optical codes and active display pigments for color switching. In this work, a stratified laminar flow of concentrated silica particles is employed, formed in a cylindrical microchannel, to produce cylindrical photonic microparticles with multiple compartments. To accomplish this, a microfluidic device is designed to have one cylindrical main channel connected with four branch channels. Four different photocurable suspensions are independently injected through the branches to form quarter‐cylindrically compartmentalized streams in the main channel. Local ultraviolet irradiation on the main channel polymerizes the suspension, thereby forming cylindrical microparticles with four compartments. In each compartment, silica particles form ordered array which develops particle size–dependent structural color. Therefore, different colors can be incorporated into single microcylinder by employing different sizes of silica particles. Moreover, one of the compartments can be rendered to be magnetoresponsive by embedding aligned magnetic particles, which enables the remote control of microcylinder orientation and therefore the switching of structural colors. 相似文献
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Sanghyuk Park;Shin-Hyun Kim; 《Advanced materials (Deerfield Beach, Fla.)》2024,36(4):2309938
Colloidal crystals display photonic stopbands that generate reflective structural colors. While micropatterning offers significant value for various applications, the resolution is somewhat limited for conventional top-down approaches. In this work, a simple, single-step bottom-up approach is introduced to produce photonic micropatterns through depletion-mediated regioselective growth of colloidal crystals. Lithographically-featured micropatterns with planar surfaces and nano-needle arrays as substrates are employed. Heterogeneous nucleation is drastically suppressed on nano-needle arrays due to minimal particle-to-needles overlap of excluded volumes, while it is promoted on planar surfaces with large particle-to-plane volume overlap, enabling regioselective growth of colloidal crystals. This strategy allows high-resolution micropatterning of colloidal photonic crystals, with a minimum feature size as small as 10 µm. Stopband positions, or structural colors, are controllable through concentration and depletant and salt, as well as particle size. Notably, secondary colors can be created through structural color mixing by simultaneously crystallizing two different particle sizes into their own crystal grains, resulting in two distinct reflectance peaks at controlled wavelengths. The simple and highly reproducible method for regioselective colloidal crystallization provides a general route for designing elaborate photonic micropatterns suitable for various applications. 相似文献
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Jong Bin Kim Hwan-Young Lee Changju Chae Su Yeon Lee Shin-Hyun Kim 《Advanced materials (Deerfield Beach, Fla.)》2024,36(9):2307917
Direct ink writing (DIW) stands out as a facile additive manufacturing method, minimizing material waste. Nonetheless, developing homogeneous Bingham inks with high yield stress and swift liquid-to-solid transitions for versatile 3D printing remains a challenge. In this study, high-performance Bingham inks are formulated by destabilizing silica particle suspensions in acrylate-based resin. A colloidal network forms in the shear-free state through interparticle attraction, achieved by disrupting the solvation layer of large resin molecules using polar molecules. The network is highly dense, with evenly distributed linkage strength as monodisperse particles undergo gelation at an ultra-high fraction. Crucially, the strength is calibrated to ensure a sufficiently large yield stress, while still allowing the network to reversibly melt under shear flow. The inks immediately undergo a liquid-to-solid transition upon discharge, while maintaining fluidity without nozzle clogging. The dense colloidal networks develop structural colors due to the short-range order. This enables the rapid and sophisticated drawing of structurally-colored 3D structures, relying solely on rheological properties. Moreover, the printed composite structures exhibit high mechanical stability due to the presence of the colloidal network, which expands the range of potential applications. 相似文献
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The synthesis and assembly of monodispersed colloidal spheres are currently the subject of extensive investigation to fabricate artificial structural color materials. However, artificial structural colors from general colloidal crystals still suffer from the low color visibility and strong viewing angle dependence which seriously hinder their practical application in paints, colorimetric sensors, and color displays. Herein, monodispersed polysulfide (PSF) spheres with intrinsic high refractive index (as high as 1.858) and light‐absorbing characteristics are designed, synthesized through a facile polycondensation and crosslinking process between sodium disulfide and 1,2,3‐trichloropropane. Owing to their high monodispersity, sufficient surface charge, and good dispersion stability, the PSF spheres can be assembled into large‐scale and high‐quality 3D photonic crystals. More importantly, high structural color visibility and broad viewing angle are easily achieved because the unique features of PSF can remarkably enhance the relative reflectivity and eliminate the disturbance of scattering and background light. The results of this study provide a simple and efficient strategy to create structural colors with high color visibility, which is very important for their practical application. 相似文献
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空间微重力环境下几乎无对流和沉降,可为晶体生长提供一个相对稳定和均一的理想环境,易于得到尺寸较大的高质量单晶。但是,空间结晶实验成功率低,费用昂贵,实验机会受限。因此,研发各种空间微重力环境地基模拟技术具有重要意义。目前可用于晶体生长的地基无容器悬浮技术主要有空气动力悬浮、静电悬浮、电磁悬浮、液体界面悬浮、超声悬浮和磁场悬浮技术等。这些地基模拟技术可实现晶体的无容器悬浮生长,避免器壁对晶体生长的不良影响,提高晶体质量,为解决X射线单晶衍射技术中的瓶颈问题提供新途径,还可为在地基进行结晶动力学和机理研究提供简单易行的方法。从技术原理、优势、缺陷及在结晶(特别是蛋白质结晶)中的应用4个方面对这些技术逐一进行了介绍和评述。重点介绍了液体界面悬浮、超声悬浮和磁场悬浮技术这3种用于蛋白质晶体生长的较为成熟的地基无容器悬浮技术。 相似文献
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Jaspreet Walia Navneet Dhindsa Mohammadreza Khorasaninejad Simarjeet Singh Saini 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(1):144-151
Tunable structural color generation from vertical silicon nanowires arranged in different square lattices is demonstrated. The generated colors are adjustable using well‐defined Bragg diffraction theory, and only depend on the lattice spacing and angles of incidence. Vivid colors spanning from bright red to blue are easily achieved. In keeping with this, a single square lattice of silicon nanowires is also able to produce different colors spanning the entire visible range. It is also shown that the 2D gratings also have a third grating direction when rotated 45 degrees. These simple and elegant solutions to color generation from silicon are used to demonstrate a cost‐effective refractive index sensor. The sensor works by measuring color changes resulting from changes in the refractive index of the medium surrounding the nanowires using a trichromatic RGB decomposition. Moreover, the sensor produces linear responses in the trichromatic decomposition values versus the surrounding medium index. An index resolution of 10?4 is achieved by performing basic image processing on the collected images, without the need for a laser or a spectrometer. Spectral analysis enables an increase in the index resolution of the sensor to a value of 10?6, with a sensitivity of 400 nm/RIU. 相似文献
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目的综述聚多巴胺在结构显色领域的应用及国内外的研究进展,为进一步研究结构显色功能材料在印刷颜料、显示、隐身、防伪、智能材料以及显色传感器等领域的应用提供理论依据。方法总结国内外聚多巴胺应用于结构色材料的研究现状,简单介绍聚多巴胺的反应机理、性能特征以及提纯方法,并重点分析该材料在结构显色领域的应用和进展,以及对聚多巴胺在结构色材料的应用方面所面临的挑战和发展趋势加以总结。结论将聚多巴胺与晶体材料结合,可制备出具有高饱和度、各向同性以及绿色环保的结构色材料,在印刷、包装、传感等相关领域具有非常大的潜在应用价值,为未来结构显色领域的研究提供了新思路。 相似文献
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AbstractIn this paper, the key topics of tunable structural color in biology and material science are overviewed. Color in biology is considered for selected groups of tropical fish, octopus, squid and beetle. It is caused by nanoplates in iridophores and varies with their spacing, tilting angle and refractive index. These examples may provide valuable hints for the bioinspired design of photonic materials. 1D multilayer films and 3D colloidal crystals with tunable structural color are overviewed from the viewpoint of advanced materials. The tunability of structural color by swelling and strain is demonstrated on an example of opal composites. 相似文献
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Kyu‐Tae Lee Sungyong Seo Jae Yong Lee L. Jay Guo 《Advanced materials (Deerfield Beach, Fla.)》2014,26(36):6324-6328
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