Feng Ji, Liu Zheng, Gao Tong, Gigmes Didier, Morlet-Savary Fabrice, Schmitt Michael, Dietlin Celine, Petithory Tatiana, Pieuchot Laurent, Zhang Jing, Shan Wenpeng, Xiao Pu, Dumur Frédéric, Lalevée Jacques
Université de Haute-Alsace, CNRS, IS2M UMR7361, Mulhouse, F-68100, France.
Université de Strasbourg, Strasbourg, 67000, France.
Small. 2025 Feb;21(5):e2411888. doi: 10.1002/smll.202411888. Epub 2024 Dec 18.
Currently, there are only few reports on water-soluble photoinitiating systems. In this study, a highly water-soluble organic dye i.e. sodium (E)-3,3'-((4-(2-(3-methylbenzo[d]thiazol-3-ium-2-yl)vinyl)phenyl)azanediyl)dipropionate iodide, was synthesized and served as a photoinitiator. Notably, this water-soluble initiator, at a low concentration of just 0.01 wt%, demonstrates a high photoinitiation ability, with some hydrogel formulations achieving nearly 100% double bond conversion under sunlight. Photopolymerization kinetics were monitored using Real-Time Fourier Transform Infrared. To explore the complex chemical principles of radical polymerization, UV-visible absorption and fluorescence spectroscopy, steady-state photolysis, fluorescence quenching experiments and cyclic voltammetry were employed to gain a comprehensive understanding of the photochemical mechanism involved. Additionally, several characteristics of the synthesized hydrogels were also investigated i.e. the water content, the water swelling, and the volume swelling. In addition to their excellent photoinitiation capabilities, the hydrogel formulations developed in this study also supported 3D printing. 3D objects with smooth surface and a high spatial resolution could be successfully printed using direct laser writing. The fabricated hydrogels could reversibly change of shape in response to water (adding or removing water), enabling successful 4D printing behavior. Furthermore, the efficient photoinitiation ability of the water-soluble formulations opens new avenues for sunlight-polymerized hydrogels and potential applications in bioprinting.
目前，关于水溶性光引发体系的报道较少。在本研究中，合成了一种高度水溶性的有机染料，即(E)-3,3'-((4-(2-(3-甲基苯并[d]噻唑-3-鎓-2-基)乙烯基)phenyl)偶氮二基)二丙酸碘化物钠，并将其用作光引发剂。值得注意的是，这种水溶性引发剂在仅0.01 wt%的低浓度下就表现出高的光引发能力，一些水凝胶配方在阳光下双键转化率接近100%。使用实时傅里叶变换红外光谱监测光聚合动力学。为了探索自由基聚合的复杂化学原理，采用紫外-可见吸收光谱、荧光光谱、稳态光解、荧光猝灭实验和循环伏安法来全面了解所涉及的光化学机理。此外，还研究了合成水凝胶的几个特性，即含水量、水溶胀和体积溶胀。除了具有优异的光引发能力外，本研究中开发的水凝胶配方还支持3D打印。使用直接激光写入可以成功打印出表面光滑且空间分辨率高的3D物体。制备的水凝胶可以响应水（加水或脱水）可逆地改变形状，实现成功的4D打印行为。此外，水溶性配方的高效光引发能力为阳光聚合水凝胶及其在生物打印中的潜在应用开辟了新途径。
