Fluorescent hydrogel with high toughness response based on lanthanide Metals: Material Adhesion, multicolor Modulation, information encryption

Natural polymer-based luminescent materials (NPLMs) are widely used in various fields of science and technology during the high-tech era. This study describes the formation of polyacrylamide (PAM) by thermally initiated free radical in situ polymerization of acrylamide monomer. The resulting hydrogel is physically entangled and chemically crosslinked with hypromellose (HPMC) to create a three-dimensional network structure. Lanthanide organic compatibilizers (Ln-L) are then introduced as luminescent units to produce fluorescent hydrogel materials. The study found that the tensile strength of PAM/HPMC/Ln (0/6 Eu/Tb) hydrogel increased by 230.53 % from 11.76 to 27.11 MPa. Similarly, the compressive strength increased by 208.30 % from 16.14 to 33.62 MPa. Additionally, by adjusting the molar ratio of lanthanide metals, hydrogels can achieve colorful fluorescence modulation. Moreover, an information encryption function was implemented using a Python design program in combination with the fluorescent properties of hydrogels.