Lanthanides-based security inks with reversible luminescent switching and self-healing properties for advanced anti-counterfeiting

The development of advanced luminescent anti-counterfeiting materials with self-healing ability is still a challenging task. Herein, the security inks with reversible luminescent switching and self-healing properties were easily prepared by doping lanthanides complexes into self-healable poly (2-acrylamido-2-methyl-1-propanesulfonicacid) (PAMPSA) matrix. The security inks exhibited reversible luminescent “on–off” switching in response to “base-acid” vapors, it allowed themselves as good candidates for realizing reversible information decryption and encryption. The confidential information fabricated by security inks could not be identified under daylight and/or UV light, which could only be recognized after the treatment with NH 3 vapor in the presence of UV light. Importantly, the information can be further encrypted and decrypted by HCl vapor and NH 3 vapor, respectively, it can avoid the second leakage of confidential information as well as realize the repeated reading of confidential information. The rational designed multiple encryption strategies were also demonstrated to further improve anti-counterfeiting level. Remarkably, the security inks exhibited good self-healing ability to extend their service life and ensure durability, which is very important for their practical applications. In addition, the obtained inks exhibited excellent stability against UV irradiation, humidity, organic solvents, heating, and rubbing. The inks also exhibited good stability in ambient conditions and can be written on various substrates. The above results indicated that the as-prepared security inks have tremendous potential applications in advanced anti-counterfeiting.