作者
Yijun Yao,J. S. Xue,Miao Wang,Dong Fu,Yanqin Shen,Ying Xue,Fan Zhang,Pengbi Liu,Hongru Wang,Hailiang Wu
摘要
Herein, a facile, green, and universal method to prepare polymer fluorescent films was proposed. Firstly, hollow cellulose-based microspheres were prepared by cross-linking copolymerization and self-assembly strategy. Then, after encapsulating the hydrophobic fluorescent dye fluorescein isothiocyanate (FITC) into the cavity of a hollow cellulose-based microsphere through the ultrasonic/dialysis method, a series of flexible fluorescent microsphere films with tunable fluorescence was obtained. The formation of hollow cellulose-based microspheres was confirmed by SEM. DLS, AFM, and UV–vis analysis provided evidences for the successful encapsulation of FITC in hollow cellulose-based microspheres. Benefiting from the synergistic effects of "anchoring", "diluting" and "isolation" for cellulose polymer chain as well as the hollow structure, the aggregation and self-quenching of FITC were effectively inhibited, which promoted the fluorescent films with different loading amount to emit green fluorescence under 365 nm UV light irradiation, and the fluorescence intensity was tunable. Moreover, the fluorescent films exhibited strong UV absorption, excellent optical stability, foldability, and easy scrollability. Particularly, compared with the luminescent film constructed by whisker-like cellulose-based microgel, the hollow cellulose-based fluorescent microsphere film obtained in this work had higher solvent resistance, water contact angle, and thermal stability. Due to the high stability and easy processability of hollow cellulose-based fluorescent microspheres, they could be processed into coating materials and fibers that were durable and widely used. They have potential application value in the fields of light-emitting devices, safety warnings, smart labels, and anti-counterfeiting materials, etc.