Fluorescent Composite Hydrogel of Carboxymethyl Celluose-Eu(Ⅲ)/Polyvinyl Alcohol and Its Application in Functional Paper

Abstract A novel carboxymethyl cellulose-Europium(Ⅲ)/polyvinyl alcohol (CMC-Eu(Ⅲ)/PVA) fluorescent hydrogel was prepared by a green and facile method. The hydrogel formed a physical cross-linking network under mild reaction conditions without using volatile organic chemical reagents. A porous structure was formed by the hydrogen bonding and other interaction between the PVA chains and the free hydroxyl on CMC-Eu(Ⅲ) during the composite gel transformation process. The addition of CMC-Eu(Ⅲ) improved the tensile and compressive mechanical properties of PVA hydrogel. When the CMC-Eu(Ⅲ) content was 15%, the maximum tensile stress of the composite hydrogel was 47.25±10.35 kPa and the compressive stress was 10.14±1.90 kPa. Meanwhile, the CMC-Eu(Ⅲ)/PVA hydrogels exhibited a 5D0→7F2 characteristic emission peak of Eu3+ at 615 nm, and emitted stable red fluorescence under UV irradiation at 254 nm. Moreover, the hydrogel was applied in making fluorescent paper as an internal sizing agent. When the amount of hydrogel was 1%, the tensile strength of fluorescent paper reached 3.52 kN/m, which is promising in the application of anti-counterfeiting.