Title: Geminate Labels Programmed by Two-tone Microdroplets Combining Structural and Fluorescent Color

Author: Lang Qin, Xiaojun Liu, Kunyun He, Guodong Yu, Hang Yuan, Ming Xu, Fuyou Li, Yanlei Yu*

Journal: Nat. Commun., 2021, 12(1), 699

Abstract:

Creating a security label that carries entirely distinct information in reflective and fluorescent states would enhance anti-counterfeiting levels to deter counterfeits ranging from currencies to pharmaceuticals, but has proven extremely challenging. Efforts to tune the reflection color of luminescent materials by modifying inherent chemical structures remain outweighed by substantial trade-offs in fluorescence properties, and vice versa, which destroys the information integrity of labels in either reflection or fluorescent color. Here, a strategy is reported to design geminate labels by programming fluorescent cholesteric liquid crystal microdroplets (two-tone inks), where the luminescent material is ‘coated’ with the structural color from helical superstructures. These structurally defined microdroplets fabricated by a capillary microfluidic technique contribute to different but intact messages of both reflective and fluorescent patterns in the geminate labels. Such two-tone inks have enormous potential to provide a platform for encryption and protection of valuable authentic information in anti-counterfeiting technology.

论文链接：https://www.nature.com/articles/s41467-021-20908-y

PDF下载：Geminate Labels Programmed by Two-tone Microdroplets Combining Structural And Fluorescent Color.pdf

研究团队首先合成了一种与液晶结构相似且量子效率高的氰基取代低聚（对亚苯基亚乙烯基）衍生物DC5作为荧光分子。接着，将该分子掺杂在胆甾相液晶E7中，并改变手性掺杂剂的含量来调控螺距。同时，借助毛细管微流控技术即可获得不同结构色的荧光胆甾相液晶乳液微球。通过将结构色可调、荧光性质稳定的“双色”微球与只有结构色的“单色”微球结合，可构筑在反射和荧光模式下分别携带完全不同信息的安全标签，实现了信息加密的概念验证。