Abstract A multifunctional fluorescent polyurethane (MFP) with solid-state and acid-base responsive fluorescence emission was reported by bonding 1,5-dihydroxy naphthalene(1,5-DN) into polyurethane backbone. The structure of MFP was confirmed by characterization with 1H NMR, FTIR and UV spectra. The fluorescent emission property and acid-base response behavior of MFP samples were studied on fluorescence spectrophotometer. The structural characterization revealed that 1,5-dihydroxy naphthalene was introduced into the polyurethane chain in the form of chemical bond. The physical entanglement and interactions of polymer chains could limit the strong π-π stacking between 1,5-DN. Therefore, MFP exhibited an obvious fluorescence emission at around 460 nm both in solution and solid state, which indicated that the “aggregation-caused quenching” (ACQ) phenomenon had been successfully eliminated. More interestingly, we found that the MFP solution samples have different fluorescence emission wavelengths in the acid (490 nm, blue-green light) and base (460 nm, blue light) environments, with a maximum displacement of over 30 nm. Meanwhile, the fluorescence intensity in strong base (pH = 11) environment decreased by 89% compared with that in strong acid (pH = 3) environment. Base on the dual feature response behavior, MFP has the potential to be used for double signal detection in strong acid and base environments.

中文翻译：

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一种具有固态和酸碱响应荧光发射的多功能聚氨酯

摘要 通过将1,5-二羟基萘(1,5-DN) 键合到聚氨酯主链上，报道了一种具有固态和酸碱响应荧光发射的多功能荧光聚氨酯(MFP)。MFP 的结构通过 1H NMR、FTIR 和 UV 光谱表征得到证实。在荧光分光光度计上研究了MFP样品的荧光发射特性和酸碱响应行为。结构表征表明，1,5-二羟基萘以化学键的形式引入聚氨酯链中。聚合物链的物理缠结和相互作用可以限制 1,5-DN 之间的强 π-π 堆积。因此，MFP 在溶液和固态均在 460 nm 附近表现出明显的荧光发射，这表明“聚集引起的淬火”（ACQ）现象已经成功消除。更有趣的是，我们发现MFP溶液样品在酸性（490 nm，蓝绿光）和碱性（460 nm，蓝光）环境下具有不同的荧光发射波长，最大位移超过30 nm。同时，强碱（pH=11）环境下的荧光强度比强酸（pH=3）环境下的荧光强度降低了89%。基于双特征响应行为，MFP 有可能用于强酸和强碱环境中的双信号检测。蓝光）环境，最大位移超过 30 nm。同时，强碱（pH=11）环境下的荧光强度比强酸（pH=3）环境下的荧光强度降低了89%。基于双特征响应行为，MFP 有可能用于强酸和强碱环境中的双信号检测。蓝光）环境，最大位移超过 30 nm。同时，强碱（pH=11）环境下的荧光强度比强酸（pH=3）环境下的荧光强度降低了89%。基于双特征响应行为，MFP 有可能用于强酸和强碱环境中的双信号检测。