Duan Huatian, Zhang Jincheng, Weng Yuchen, Fan Zhinan, Fan Li-Juan
State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, Department of Polymer Science and Engineering, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China.
ACS Appl Mater Interfaces. 2022 Jul 20;14(28):32510-32521. doi: 10.1021/acsami.2c06965. Epub 2022 Jul 11.
Developing a new anti-counterfeiting strategy is of great significance to combating the global counterfeiting problem. Here we report the construction of a dynamic fluorescence response system for anti-counterfeiting by combining the photochromism induced by the ring-opening of spiropyran (SP) to merocyanine (MC) with the fluorescence resonance energy transfer (FRET) between the conjugated polymer and MC. After elucidating the design principle, a new conjugated polymer, PPETE-SP, consisting of a poly[-(phenylene ethynylene)--(thienylene-ethynylene)] (PPETE) backbone with pendant SP, was synthesized and characterized. With poly(methyl methacrylate) (PMMA) as the matrix, the PPETE-SP/PMMA fibrous membrane was prepared via electrospinning. Under the irradiation of UV light, the fluorescent color of the membrane dynamically changed from green to light green, then light pink, and finally pink, and this process was reversible under visible light. The fluorescence emission switch was examined for 10 cycles and proved to have good repeatability, indicating that the membrane can be directly used as an anti-counterfeiting label for multiple verifications. The FRET efficiency was found to be about 61% based on the FRET study with confocal laser scanning microscopy. The covalent bonding between PPETE backbone and SP, the confinement of PPETE-SP chains in the fibrous membrane, as well as employing PMMA as the matrix were demonstrated to be crucial in realizing the photochromism and the FRET. Different anti-counterfeiting modes were proposed, providing rich selections for operation of verification. Such facile-to-operate and hard-to-imitate dynamic fluorescent responsive materials are very promising for use in practical anti-counterfeiting applications.
制定新的防伪策略对于应对全球假冒问题具有重要意义。在此，我们报告了一种用于防伪的动态荧光响应系统的构建，该系统通过将螺吡喃（SP）开环生成部花青（MC）所诱导的光致变色与共轭聚合物和MC之间的荧光共振能量转移（FRET）相结合。在阐明设计原理后，合成并表征了一种新的共轭聚合物PPETE-SP，它由带有侧链SP的聚[-(亚苯基乙炔基)-(噻吩基-乙炔基)]（PPETE）主链组成。以聚甲基丙烯酸甲酯（PMMA）为基质，通过静电纺丝制备了PPETE-SP/PMMA纤维膜。在紫外光照射下，膜的荧光颜色从绿色动态变为浅绿色，然后变为浅粉色，最后变为粉色，并且在可见光下这个过程是可逆的。对荧光发射开关进行了10个循环的测试，证明具有良好的重复性，这表明该膜可直接用作多次验证的防伪标签。基于共聚焦激光扫描显微镜的FRET研究发现FRET效率约为61%。结果表明，PPETE主链与SP之间的共价键、PPETE-SP链在纤维膜中的限制以及采用PMMA作为基质对于实现光致变色和FRET至关重要。提出了不同的防伪模式，为验证操作提供了丰富的选择。这种易于操作且难以模仿的动态荧光响应材料在实际防伪应用中具有很大的应用前景。
