CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology (NCNST), No. 11 ZhongGuanCun BeiYiTiao, Beijing, 100190, P. R. China.
University of Chinese Academy of Sciences, Beijing, 100049, P. R. China.
Adv Sci (Weinh). 2022 Jul;9(20):e2201565. doi: 10.1002/advs.202201565. Epub 2022 May 1.
Creating a security material that carries distinct information in reflective color, fluorescence, and chiroptical property will enhance anti-counterfeiting levels to deter counterfeits ranging from currencies to pharmaceuticals, but is proven extremely challenging. In this work, an advanced anti-counterfeiting material, with three-state of each mode reversibly converted into multi-mode materials including reflective color, fluorescence, and circularly polarized luminescence signal, is constructed by loading photofluorochromic spiropyran (SP) and zinc ion (Zn ) into the chiral liquid crystal. Under UV irradiation, the complexes of SP and Zn will be transformed into merocyanine (MC) and MC-Zn , while the energy transfer occurs from MC-Zn to MC. Upon heating, MC is easy to recover to SP, while the MC-Zn remains unchanged. The MC and MC-Zn can be transformed into the SP and Zn under visible light irradiation. The three states of each mode can reversibly convert. Furthermore, the reflective color or fluorescence of each state shows different intensities under left- and right-handed circular polarized filters, enabling easy distinguishing by naked eyes. The advanced anti-counterfeiting method with multi-state of each mode for multi-mode encryption information output will provide a new concept for designing and fabricating multi-mode anti-counterfeiting materials, improving the security level for practical application.
创建一种具有反射色、荧光和手性光学特性的独特信息的安全材料，将提高防伪水平，以阻止从货币到药品等各种假冒产品的出现，但事实证明这极具挑战性。在这项工作中，通过将光致变色螺吡喃（SP）和锌离子（Zn ）负载到手性液晶中，构建了一种先进的防伪材料，其三种模式可分别可逆转换为包括反射色、荧光和圆偏振发光信号的多模材料。在紫外光照射下，SP 和 Zn 的配合物将转变为变色酸（MC）和 MC-Zn ，同时发生从 MC-Zn 到 MC 的能量转移。加热时，MC 容易恢复到 SP，而 MC-Zn 保持不变。MC 和 MC-Zn 可在可见光照射下分别转化为 SP 和 Zn 。每种模式的三种状态均可可逆转换。此外，每种状态的反射色或荧光在左、右手圆偏振滤光片下显示出不同的强度，可通过肉眼轻松区分。这种具有多态多模加密信息输出的先进多态防伪方法将为设计和制造多模防伪材料提供新的概念，提高实际应用的安全水平。
