Waterborne rare earth complexes/polyurethane systems with UV shielding and tunable fluorescence for anti-counterfeiting
Peng Luo, Shaokui Zhou, Xinzhe Xiao, Lin Gu
Abstract
Fluorescent polymer materials integrated with rare-earth complexes demonstrate promising multifunctional capabilities. However, their complex synthesis procedures and prohibitive cost currently constrain large-scale utilization. Herein, rare earth complexes Eu(PBA) 3 Phen and Tb(PBA) 3 Phen were synthesized by coordinating Eu 3+ , Tb 3+ with p -hydroxybenzoic acid and phenanthroline , which were then physically incorporated into waterborne polyurethane (WPU) to obtain Eu-WPU and Eu/Tb-WPU composites. The as-prepared Eu/Tb-WPU had tunable fluorescence, whose fluorescent colors from green to red were achieved under ultraviolet excitation. Compared to Eu(PBA) 3 Phen (0.27 ms; 0.22 %), the Eu-WPU exhibited a prolonged fluorescence lifetime(1.08 ms) and high fluorescence quantum yield (10.7 %). In addition, Eu-WPU had a wider UV shielding range of 200–289 nm than WPU (200–222 nm). The prepared Eu/Tb-WPU exhibited rich fluorescent emission colors and can be used for information security encryption. Therefore, these Eu-WPU and Eu/Tb-WPU have good application prospects in ultraviolet shielding and fluorescence anti-counterfeiting.