Time-resolved photofluorochromism constitutes a powerful approach to enhance information encryption security but remains challenging. Herein, we report a strategy of using hydrogen bonds to regulate the time for initiating photofluorochromism. In our strategy, copolymers containing negative photochromic spiropyran (NSP), naphthalimide, and multiple hydrogen-bonding (UPy) units are designed, which display photo-switchable fluorescence resonance energy transfer (FRET) process from naphthalimide donor to the NSP acceptor. Interestingly, the FRET is locked via the dynamic hydrogen-bonding interaction between ring-opened NSP and UPy moieties, resulting in time-dependent fluorescence. The change in fluorescence can be finely regulated via UPy fraction in the polymers. Besides the novel time-dependent fluorescence, the polymers also take advantage of visible-light triggerable, excellent photostability, photoreversibility, and processability. We demonstrate that these properties enable them many application opportunities such as fluorescent security labels and multilevel information encryption patterns.

中文翻译：

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用于时间分辨信息加密和防伪的氢键相关光致荧光变色


时间分辨光致荧光变色是增强信息加密安全性的有效方法，但仍然具有挑战性。在此，我们报告了一种利用氢键来调节光致荧光变色起始时间的策略。在我们的策略中，设计了含有负光致变色螺吡喃（NSP）、萘二甲酰亚胺和多个氢键（UPy）单元的共聚物，其显示从萘二甲酰亚胺供体到NSP受体的光可切换荧光共振能量转移（FRET）过程。有趣的是，FRET 通过开环 NSP 和 UPy 部分之间的动态氢键相互作用锁定，从而产生时间依赖性荧光。荧光的变化可以通过聚合物中的 UPy 分数进行精细调节。除了新颖的时间依赖性荧光之外，该聚合物还具有可见光可触发、优异的光稳定性、光可逆性和可加工性的优点。我们证明这些特性使它们具有许多应用机会，例如荧光安全标签和多级信息加密模式。