High‐Performance Sunlight‐Induced Polymerized Hydrogels and Applications in 3D and 4D Printing

作者：Ji Feng, Zheng Liu, Tong Gao, Didier Gigmès, Fabrice Morlet‐Savary, Michael Schmitt, Céline Dietlin, Tatiana Petithory, Laurent Pieuchot, Jing Zhang, Wenpeng Shan, Pu Xiao, Frédéric Dumur, Jacques Lalevée · 发表于：Small · 年份：2024 · DOI：10.1002/smll.202411888 · 被引用次数：7 · 研究领域：Photopolymerization techniques and applications、Photochromic and Fluorescence Chemistry、Additive Manufacturing and 3D Printing Technologies

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 ...