The application of azobenzene (AZO) as a kind of photo-switch is restricted by its excitation source, i.e., UV light. Hence, visible light-driven azobenzene-based photo-switching is needed and has been designed in the work. In order to forecast the optimal triggered wavelength, the electrostatic potential, theoretical UV-vis spectra, as well as the energy gap for focused structures was calculated to describe the energy and orbit status of the molecules by DFT. According to the theoretical optimization results, m-Methyl Red (m-MR) containing copolymer was successfully synthesized as a visible light-driven photo-switch. Further, for performance evaluation, the efficiency and effectiveness of different excitation wavelengths was firstly evaluated for the copolymer using m-MR and m-Methyl Red acrylic anhydride (m-MRAA) as the controls. Compared with m-MR and m-MRAA, the copolymer exhibited outstanding characteristics as a photo-switch according to its response–recovery behavior. At the same time, blue light proved to be the most efficient excitation light source. Moreover, the equilibrium response time and recovery time showed some dependence on the excitation wavelength. Secondly, the influence of the light intensity on the isomerization transition was investigated. A relatively low light density could lead to a relatively low degree of the final cis form and needed more equilibrium time for trans to cis transformation but showed little effect on the recovery process. Thirdly, repeatable on/off irradiation was used to evaluate the fatigue resistance of the copolymer. Good fatigue resistance without photobleaching was verified from the results. Fourthly, the influence of the solvent on visible light-driven isomerization was also evaluated. Finally, the synthesized copolymer still had the characteristic of a pH indicator with a critical point at pH 5.0 and exhibited an obvious fluorescent characteristic.

中文翻译：

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可见光驱动的光开关大分子的设计、合成和研究

偶氮苯(AZO)作为一种光开关的应用受到其激发源即紫外光的限制。因此，需要可见光驱动的基于偶氮苯的光开关，并且已经在工作中进行了设计。为了预测最佳触发波长，计算了静电势、理论紫外-可见光谱以及聚焦结构的能隙，以通过 DFT 描述分子的能量和轨道状态。根据理论优化结果，m-甲基红（m-MR) 的共聚物成功合成为可见光驱动的光开关。此外，为了进行性能评估，首先使用m -MR 和m -甲基红丙烯酸酐 ( m -MRAA) 作为对照，评估了共聚物在不同激发波长下的效率和有效性。与m -MR 和m相比-MRAA，该共聚物根据其响应-恢复行为表现出作为光开关的出色特性。同时，蓝光被证明是最有效的激发光源。此外，平衡响应时间和恢复时间对激发波长有一定的依赖性。其次，研究了光强对异构化转变的影响。相对较低的光密度可能导致最终顺式形式的程度相对较低，并且需要更多的反式到顺式的平衡时间转化，但对恢复过程影响不大。第三，使用可重复的开/关辐照来评估共聚物的抗疲劳性。从结果验证了良好的耐疲劳性而没有光漂白。第四，还评估了溶剂对可见光驱动异构化的影响。最后，合成的共聚物仍具有pH 5.0临界点的pH指示剂特性，并表现出明显的荧光特性。