Cracking enabled unclonability in colloidal crystal patterns authenticated with computer vision

Li, Yuhuan; Mao, Yexin; Wang, Jiahui; Liu, Zhiwei; Jia, Pan; Wu, Na; Yu, Hongbo; Wang, Jinqiao; Song, Yanlin; Zhou, Jinming

doi:10.1039/d2nr01479c

Cited by 29 publications

(18 citation statements)

References 54 publications

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“…Photonic crystals (PCs) are optical materials or structures that change their refractive index regularly. − When compared to conventional dyes and pigment colorants, structure colors have the advantages of being less expensive, having a higher luminosity tolerance, and being environmentally friendly. , Janus particles are isotropic particles with two different chemical and physical compositions distributed on the same surface. − Janus particles with structure color and stimulus-response have piqued the interest of researchers for a variety of applications including display materials, drug delivery systems, , sensors, − and so on. Photonic crystals are widely studied for anti-counterfeiting applications due to their structural color and stimulus responsiveness. − Lee et al deposited Fe nanoparticles on photonic crystal microspheres, which shifted to different degrees under different magnetic field angles, and the photonic band gap position changed as a result . Li et al fabricated unconventional structural-color anti-counterfeiting labels with physically unclonable functions (PUFs) fabricated by the facile and scalable inkjet printing method .…”

Section: Introductionmentioning

confidence: 99%

Magnetic–Fluorescent Responsive Janus Photonic Crystal Beads for Self-Destructive Anti-counterfeiting

et al. 2022

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In this study, we fabricate magnetic–fluorescent responsive Janus photonic crystal beads (JPCBs) based on poly(styrene-methyl methacrylate-acrylic acid) (p(St-MMA-AA)) colloidal nanoparticles, Fe3O4, and photobase generators used for self-destructive anti-counterfeiting. We synthesize two kinds of photobase generators that can react with fluorescamine to produce various fluorescence colors. A microfluidic method is used to obtain the Janus photonic crystal beads. The upper portions of the JPCBs are photonic crystals assembled with colloidal spheres, whereas the Fe3O4 settles down to the bottom of the JPCBs due to its higher density. Photobase generators are distributed in photonic crystal gaps. Because of the magnetism of the Fe3O4, the JPCBs could be flipped from one side to the other in the presence of a magnet. After being exposed to UVC light and fluorescamine, the JPCBs can fluoresce under UVA light. Then, we create Janus microbeads arrays with various types of beads and apply them to the visitor card, bracelet, and box label to provide irreversible and self-destructive anti-counterfeiting. The JPCBs are capable of being encoded and angle-independently displayed, which are crucial to their applications in anti-counterfeiting, information coding, and array display.

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Section: Introductionmentioning

confidence: 99%

Magnetic–Fluorescent Responsive Janus Photonic Crystal Beads for Self-Destructive Anti-counterfeiting

et al. 2022

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“…Inspired by these, artificial chameleon skins [ 6–16 ] have been extensively investigated to mimic the characteristics of the dynamic change of colors, which are potentially useful for optical devices, [ 17–19 ] displays, [ 20–26 ] sensing, [ 7,18,19,27–34 ] printing, [ 11,35–39 ] and anticounterfeiting. [ 8,40–54 ] In striking contrast, passive camouflage can be found in insects, [ 1 ] such as Closterocerus coffeelate and Drosophila melanogaster , whose wings are transparent and iridescent in front of a white and black background, respectively. Such unique off/on characteristics of structural colors are important and meaningful for considerable applications, nevertheless, it is still challenging to realize the unique off/on functions.…”

Section: Introductionmentioning

confidence: 99%

Artificial Chameleon Skins Active Mimicking Reversible Off/On Structural Colors of Insect Wings

Zhang

Wei

Yang

et al. 2022

Adv Materials Inter

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In nature, chameleons and insect wings show characteristics of actively tunable and passively off/on structural colors, respectively, which is crucial for them to camouflage and survival. Inspired by these, photonic crystal (PC) gels possessing chameleon's nonclose‐packing structures can actively mimic the reversible off/on characteristics of the structural colors of insect wings are designed. The PC gels with outstanding tailorable, bendable, and twistable properties are prepared by nonclose‐assembling silica particles in polymers and swelling in solvents. Interestingly, the PC gels exhibit high transparency (>95%) in water because of the matching of the refractive index (Δn = 0) but show brilliant and tunable structural colors in other solvents due to the Δn ≠ 0. The switching between the off/on colors can be completed in tens of seconds. Based on these advantages, the PC gels are used to actively camouflage and fabricate invisible patterns that are transparent in water but revealable in other solvents. This work offers a straightforward and efficient way to build PC gels with solvents‐responsive off/on color characteristics, showing great potential in camouflage, anticounterfeiting, and optical devices.

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“…In 2017, this group first reported a self-healing organogel based on amorphous photonic crystals . The group subsequently reported a series of structural color materials combined with computer vision for physically unclonable anticounterfeiting patterns. − The above areas require better analysis and control of structural colors. Unfortunately, most of the analysis of the PBG still uses spectrometers and the naked eye, and there is a lack of accurate quantitative analysis of structural colors.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Analysis of Structure Color of Photonic Crystal Sensors Based on HSB Color Space

Zhang

Qiu

Shea

et al. 2022

ACS Appl. Mater. Interfaces

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The photonic crystals (PhCs) have a bright structural color, but their angular dependence and naked-eye observation subjectivity only apply for qualitative analysis. The HSB color space is a three-channel color analysis technology based on hue (H)–saturation (S)–brightness (B). We use the HSB color space to analyze the structural color of the AM/NIPAM PhCs hydrogel sensor in response to temperature and organic solvents. We proved that the structural color analysis based on the hue value (H) could achieve an analysis accuracy close to the spectrum analysis. In addition, we have obtained stimulus-responsive PhCs structure color images from references and quantitatively analyzed them through the HSB color space. The results show that the H of the structural color can establish a high correlation with the specified target. In some cases, its best fitness exceeds traditional spectroscopy methods. This analysis method will provide a general and quantitative analysis technology for the structural color of PhCs by consumer-grade computers and smartphones.

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Cracking enabled unclonability in colloidal crystal patterns authenticated with computer vision

Abstract: Colloidal crystals with iridescent structural coloration have appealing applications in the fields of sensors, displays, anti-counterfeiting and etc. A serious issue accompanying the facile chemical self-assembly approach to colloidal crystals...

Cited by 29 publications

References 54 publications

Magnetic–Fluorescent Responsive Janus Photonic Crystal Beads for Self-Destructive Anti-counterfeiting

Magnetic–Fluorescent Responsive Janus Photonic Crystal Beads for Self-Destructive Anti-counterfeiting

Artificial Chameleon Skins Active Mimicking Reversible Off/On Structural Colors of Insect Wings

Quantitative Analysis of Structure Color of Photonic Crystal Sensors Based on HSB Color Space

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