Preparation of a Transparent Photoluminescent Self-Healable Smart Ink for a Dual-Mode Security Authentication

Abstract

Ultraviolet-induced photochromism has been an attractive dual-mode security encoding approach to enhance the anticounterfeiting performance of commercial products. However, photochromic inks have recently reported major drawbacks, including high cost, low efficacy, and poor durability. Herein, we report the development of self-healing security ink using poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) immobilized with rare-earth-activated aluminate nanoparticles for advanced anticounterfeiting applications. Remarkably, self-healable security inks can ensure durability and photostability. The self-healing composite ink demonstrated ultraviolet-induced photochromism with high reversibility and photostability. Various self-healing composite inks of diverse emission properties were developed using various concentrations of rare-earth-activated aluminate nanoparticles. Homogeneous films were printed onto paper sheets, demonstrating a colorless appearance that changed to green under ultraviolet rays as proved by the CIE Lab. The morphological properties of the phosphor were examined, demonstrating a particle diameter of 4–9 nm. Various analytical methods were used to investigate the morphology and chemical composition of the prepared photochromic films. Both the rheological and mechanical properties of the ink solution and the ink-printed paper sheets were measured. The luminescent films had an excitation wavelength of 365 nm (colorless) and an emission peak at 520 nm (green). Various industries can benefit greatly from the current smart ink as an efficient strategy for the development of anticounterfeiting commercial products.

Quadri-Dimensional Anti-counterfeiting Flexible Label Programmed by a Photoresponsive Liquid Crystal Polymer Film

“…The widespread counterfeiting of banknotes, certificates, brands, pharmaceuticals, and jewelry has become a serious worldwide problem because of its harmful effects on the global economy, security, and health. − Developing anti-counterfeiting materials is highly desirable to increase the level of security. , Over the past few decades, various macroscopic patterns have been developed to prevent counterfeiting and information leakage, including watermarking, holograms, barcodes, and QR codes. − However, these strategies are relatively changeless and easy to copy . Therefore, photoresponsive materials have attracted accumulated attention due to their variable color or fluorescence triggered by light, − providing tremendous potential for information encryption. , Among these photoresponsive systems, liquid crystal (LC) performs excellently in tunability and responsiveness .…”

Hydrothermal deposition synthesis of dual‐mode luminescent material GdVO4:Eu3+/carbon dots with optimal luminescence and its application in anti‐counterfeiting

“…Based on this work, Li et al fabricated a dual-mode fluorescent composite material NaYF 4 :Yb,Er (Tm)/CDs via a straightforward solvothermal method and used it as ink in the anti-counterfeiting field [13]. Fluorescence technology is one of the most effective technical methods for high-tech anticounterfeiting, and the composites combined with different materials can show their comprehensive properties in practical applications [14][15][16]. Therefore, to achieve advanced anti-counterfeiting measures, it is recommended to use composite materials for the corresponding applications.…”

Emission-Tunable Room-Temperature Phosphorescent Two-Dimensional Polymer Network via a Photo-Cross-Linking Reaction

“…Pure organic room-temperature phosphorescence (RTP) materials have attracted great attention in the fields of sensing, − data encryption, − biological imaging, − and optoelectronic components − due to their long-lifetime emission, − flexible modifications, − high signal-to-noise ratio, and excellent performance without metallic elements. − However, the efficiency and lifetime of metal-free RTP material systems are still the biggest challenges to achieve their applications. − Artificial materials with RTP properties, especially materials with adjustable functions, are hindered by complex synthesis and purification, poor processing, and sustainability. − Amorphous materials perform well in preparation and feasibility; for instance, copolymerization or film doping is often used in insulating oxygen, providing a hydrogen-bond-rich environment and helping to suppress nonradiatiive transitions. Therefore, the development of amorphous RTP materials that can solve the above problems will be very beneficial.…”