Background color dependent photonic multilayer films for anti-counterfeiting labeling

Kim, Jeong‐Min; Bak, Jae Min; Lim, Bogyu; Jung, Yu Jin; Park, Byong Chon; Park, Min Ji; Park, Jong Mok; Lee, Hyung‐il; Jung, Seo‐Hyun

doi:10.1039/d1nr08482h

Cited by 15 publications

(7 citation statements)

References 50 publications

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“…To induce a color transition using the temperature of a human hand, thermochromic dye with a color transition at 28 °C was selected with black and white color because 1D PC multilayer films display two different colors depending on the background. A black background exhibited the full visible spectrum color, and a white background displayed three different composite colors synthesized by the reflection of light, including yellow, magenta, and cyan [ 28 ].…”

Section: Resultsmentioning

confidence: 99%

Dual Responsive Dependent Background Color Based on Thermochromic 1D Photonic Crystal Multilayer Films

Kim¹,

Kim²,

Girma³

et al. 2022

Polymers

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In this paper, we present dual responsive one-dimensional (1D) photonic crystal (PC) multilayer films that utilize a high-humidity environment and temperature. Dual responsive 1D PC multilayer films are fabricated on precoated thermochromic film by sequential alternate layer deposition of photo-crosslinkable poly(2-vinylnaphthalene-co-benzophenone acrylate) (P(2VN-co-BPA)) as a high refractive index polymer, and poly(4-vinylpyrollidone-co-benzophenone acrylate) P(4VP-co-BPA) as a low refractive index polymer. The thermochromic film shows a vivid color transition from black to white at 28 °C. Three different colors of thermochromic 1D PC multilayer films are prepared by thickness modulation of P(4VP-co-BPA) layers, and the films on a black background exhibit visible spectrum color only in a high-humidity environment (over 90% relative humidity (RH)). For the three films placed on a hands display, three different composite colors are synthesized by the reflection of light, including yellow, magenta, and cyan, due to the changing of backgrounds from black to white with temperature. Additionally, the films show remarkable color transitions with reliable reversibility. The films can be applied as anti-counterfeiting labels and can be used for smart decoration films. To the best of our knowledge, this is the first report of dual response colorimetric films that change color in various ways depending on temperature and humidity changes, and we believe that it can be applied to various applications.

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Section: Resultsmentioning

confidence: 99%

Dual Responsive Dependent Background Color Based on Thermochromic 1D Photonic Crystal Multilayer Films

Kim¹,

Kim²,

Girma³

et al. 2022

Polymers

Self Cite

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show abstract

“…9 When the structural colors of encrypted areas and their surrounding background form sufficient and reversible color contrast, the encrypted information or images can be read out or hidden reversibly, thus making responsive PCs appealing as anti-counterfeiting materials. 7,[152][153][154][155][156][157] However, external stimuli, such as chemicals (ions, acid or specific molecules) or mechanical force, 5,[158][159][160][161][162][163][164][165] are usually necessary to trigger the dynamic change of structures in these systems, which may inevitably lead to inconvenience for practical applications of structurally colored anti-counterfeiting materials in our daily life. In 2017, Wu and co-workers developed a convenient computerassisted inkjet-printing method to fabricate large-scale delicate structural color patterns for anti-counterfeiting applications using dispersions containing monodisperse CdS spheres with different diameters as inks.…”

Section: Anti-counterfeiting From Intrinsic and Structural Colorsmentioning

confidence: 99%

Monodisperse colloidal spheres with a high refractive index: their synthesis, assembly and application in structural colored materials

Wei

et al. 2022

J. Mater. Chem. C

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“…[8][9][10] A variety of color changing dyes and systems were recently developed by means of stimuli-responsive mechanisms such as photochromism, thermochromism, and chemochromism. [11][12][13][14][15][16][17] Phosphorescent or excitation light dose dependent optical materials have also been introduced. [18][19][20][21] Moreover, different types of anti-counterfeiting techniques have been combined to develop multilevel anticounterfeiting materials that are increasingly difficult to imitate.…”

Section: Introductionmentioning

confidence: 99%

Smart Anti‐Counterfeiting Inks: Controlled Luminescence Polarization and Its Fixation by Photoisomerization and Subsequent Photopolymerization of Cyanostilbene‐Based Liquid Crystal Monomers

Koo

Kim

Hyeong

et al. 2023

Advanced Optical Materials

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To identify and protect authentics from counterfeits, anti‐counterfeiting materials are developed. In spite of many advances in luminescent anti‐counterfeiting materials, there is still a need for easily processible, multilevel anti‐counterfeiting materials. Here, the study reports a novel strategy for the production of smart anti‐counterfeiting inks and films using a cyanostilbene‐based liquid crystal (LC) monomer (CSRM). This smart ink is prepared by mixing CSRM and conventional nematic LC monomers. The optimized ink with a nematic mesophase is uniaxially oriented by simple shear coating for high transmittance and linearly polarized light emission. Upon subsequent irradiation with 365 nm UV light using a photomask, a phase transition to an isotropic state occurs by photoisomerization of CSRM in selected areas, resulting in unpolarized photoluminescence in those areas. Two optically different regions (UV treated and untreated) can be permanently fixed by photopolymerization under 460 nm blue light. Multilevel anti‐counterfeiting labels programmed by simple shear coating, molecular self‐assembly, selective photoisomerization, and photopolymerization fixation can provide a new insight in developing smart anti‐counterfeiting inks and films.

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Background color dependent photonic multilayer films for anti-counterfeiting labeling

Abstract: We report a color tunable background-dependent one-dimensional photonic film according to the humidity of human breath for anti-counterfeiting labels.

Cited by 15 publications

References 50 publications

Dual Responsive Dependent Background Color Based on Thermochromic 1D Photonic Crystal Multilayer Films

Dual Responsive Dependent Background Color Based on Thermochromic 1D Photonic Crystal Multilayer Films

Monodisperse colloidal spheres with a high refractive index: their synthesis, assembly and application in structural colored materials

Smart Anti‐Counterfeiting Inks: Controlled Luminescence Polarization and Its Fixation by Photoisomerization and Subsequent Photopolymerization of Cyanostilbene‐Based Liquid Crystal Monomers

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