Preparation of glass nanofiber-reinforced tricarboxylic cellulose hydrogel immobilized with phosphor nanoparticles for detection of fingerprints and anticounterfeiting applications.

Photochromic inks have been a significant certification approach to improve document anticounterfeiting efficiency. However, the weak photostability and poor durability are two of their major shortcomings. Herein, this article details the development of a photochromic and self-healable hydrogel for advanced anticounterfeiting uses. When immobilized in tricarboxylic cellulose (TCC), electrospun glass nanofibers (90-170 nm) and lanthanide-activated strontium aluminate nanoparticles (LSAN; SrAlO:Eu, Dy; 644 nm) served as reinforcing and photochromic agents, respectively. The tricarboxylic cellulose bearing three carboxylic substituents on the anhydroglucose moiety was synthesized. The nanocomposite hydrogels were developed by the freezing/thawing approach. When illuminated with ultraviolet radiation, the LSAN@TCC hydrogel exhibited remarkable photostability and reversibility. A diverse range of tricarboxylic cellulose hydrogels with variable emission features was generated by varying the quantity of LSA. The LSAN@TCC nanocomposite was transparent in daytime light; however, it has shown a greenish emission under ultraviolet light. The structural and morphological properties of the glass nanofiber-reinforced tricarboxylic cellulose dried films were determined by a wide range of spectroscopic and microscopic methods. The mechanical properties of the LSAN@TCC hydrogel-stamped sheets were examined. The transparency was verified by the excitation peak at 365 nm, and the green emission was recorded at 519 nm.