Photoswitchable fluorescent polymer nanoparticles as high-security anticounterfeiting materials for authentication and optical patterning

Abdollahi, Amin; Alidaei-Sharif, Hossein; Roghani‐Mamaqani, Hossein; Herizchi, Ata

doi:10.1039/d0tc00937g

Cited by 82 publications

(67 citation statements)

References 66 publications

(106 reference statements)

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“…Authentication of products can be done using different indicator materials, such as DNA, polymers, peptide and alloy emulsion. [ 12–15 ] Those indicator materials can be verified by identifying their unique property, such as DNA sequence, light reflectance and fluorescence. [ 16–18 ] There is a sequence of three different inspection steps to ensure that a document is genuine.…”

Section: Introductionmentioning

confidence: 99%

Production of photochromic nanocomposite film via spray‐coating of rare‐earth strontium aluminate for anti‐counterfeit applications

et al. 2021

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New photochromic film was developed toward the preparation of anti‐counterfeiting documents utilizing inorganic/organic nanocomposite enclosing a photoluminescent inorganic pigment and a polyacrylic binder polymer. To generate a translucent film from pigment/polyacrylic nanocomposite, the phosphorescent strontium aluminum oxide pigment should be well‐dispersed in the solution of the polyacrylic‐based binder without agglomeration. The photochromic nanocomposite was applied efficiently onto commercial cellulose paper documents utilizing the effective and economical spray‐coating technology followed with thermofixation. A homogeneous photochromic film was immobilized onto cellulose paper surface to introduce a transparent film changing to greenish‐yellow upon exposure to ultraviolet light as depicted by CIE coloration measurements. The photochromic effect was monitored at lowest pigment concentration (0.25 wt%). The spray‐coated paper documents exhibit two absorbance bands at 256 and 358 nm, and two fluorescence peaks at 433 and 511 nm. The morphologies of the spray‐coated documents were explored. The spray‐coated paper sheets showed a reversible photochromic effect without fatigue under ultraviolet irradiation. The rheology of the produced photochromic composites as well as the mechanical properties and photostability of the spray‐coated documents were studied.

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Section: Introductionmentioning

confidence: 99%

Production of photochromic nanocomposite film via spray‐coating of rare‐earth strontium aluminate for anti‐counterfeit applications

et al. 2021

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“…Even though digitalization is changing today’s society, currency counterfeiting or document fraud are still serious threats that weaken economies and allow criminals to have a certain freedom of movement [ 1 ]. Anti-counterfeiting techniques are continuously being improved to incorporate innovative solutions to prevent document fraud, such as luminescent nanowire-based papers, invisible photoluminescent inks or chipless-RFID technologies [ 2 , 3 , 4 ].…”

Section: Introductionmentioning

confidence: 99%

Detection of Anti-Counterfeiting Markers through Permittivity Maps Using a Micrometer Scale near Field Scanning Microwave Microscope

Gutiérrez-Cano

Catalá-Civera

Plaza-Gonzalez

et al. 2021

Sensors

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This paper describes the use of microwave technology to identify anti-counterfeiting markers on banknotes. The proposed method is based on a robust near-field scanning microwave microscope specially developed to measure permittivity maps of heterogeneous paper specimens at the micrometer scale. The equipment has a built-in vector network analyzer to measure the reflection response of a near-field coaxial probe, which makes it a standalone and portable device. A new approach employing the information of a displacement laser and the cavity perturbation technique was used to determine the relationship between the dielectric properties of the specimens and the resonance response of the probe, avoiding the use of distance-following techniques. The accuracy of the dielectric measurements was evaluated through a comparative study with other well-established cavity methods, revealing uncertainties lower than 5%, very similar to the accuracy reported by other more sophisticated setups. The device was employed to determine the dielectric map of a watermark on a 20 EUR banknote. In addition, the penetration capabilities of microwave energy allowed for the detection of the watermark when concealed behind dielectric or metallic layers. This work demonstrates the benefits of this microwave technique as a novel method for identifying anti-counterfeiting features, which opens new perspectives with which to develop optically opaque markers only traceable through this microwave technique.

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“…Roghani-Mamaqani and coworkers developed a series of photochromic and photofluorochromic SP-containing latex particles by semicontinuous emulsifier-free emulsion polymerization for anticounterfeiting and photopatterning. 70,107,108 The significant particle size variation (aggregation-disaggregation) occurred by UV light irradiation, which resulted from the electrostatic interactions and/or the π − π stacking interactions between the different particles. In addition, the polar interaction between MC molecules and functional groups affected the photoswitching behaviors of these latex particles.…”

Section: Photoresponsive Polymer Nanomaterialsmentioning

confidence: 99%

Organic photoresponsive materials for information storage: a review

et al. 2020

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Photoswitchable fluorescent polymer nanoparticles as high-security anticounterfeiting materials for authentication and optical patterning

Abstract: Spiropyran-containing stimuli-chromic flexible latex nanoparticles were synthesized for development of high-security anticounterfeiting inks with application in print-marking and finger-printing on cellulosic substrates.

Cited by 82 publications

References 66 publications

Production of photochromic nanocomposite film via spray‐coating of rare‐earth strontium aluminate for anti‐counterfeit applications

Production of photochromic nanocomposite film via spray‐coating of rare‐earth strontium aluminate for anti‐counterfeit applications

Detection of Anti-Counterfeiting Markers through Permittivity Maps Using a Micrometer Scale near Field Scanning Microwave Microscope

Organic photoresponsive materials for information storage: a review

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