Photo-cross-linking of polymeric materials generally requires an inert atmosphere because of oxygen-based inhibition and quenching of the reactive species. Here, we demonstrate the photo-oxidative cross-linking of amine-functionalized poly(dimethylsiloxane) using atmospheric oxygen as the chemical oxidant. Visible light irradiation of a metalloporphyrin or an organic sensitizer generates reactive singlet oxygen that oxidatively couples amines into imine cross-links. This facile benchtop cross-linking reaction proceeds at room temperature and results in solvent-free elastic materials after 1 h. Solid state ¹³C nuclear magnetic resonance and Fourier transform infrared spectroscopy show that the reaction produces only imine functionalities with no side products observed. The mechanical properties of these polymers were tested using tensile experiments and were found to depend on the initial loading of the sensitizer, with a maximum elongation strain of 157% and a Young’s modulus of 2.15 MPa for the highest tested amount. Photolithography is demonstrated with this cross-linking system using visible light irradiation.

中文翻译：

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使用单线态氧的可见光敏化聚硅氧烷的光氧化交联

聚合材料的光交联通常需要惰性气氛，因为基于氧的抑制和反应性物种的猝灭。在这里，我们演示了使用大气氧作为化学氧化剂的胺官能化聚二甲基硅氧烷的光氧化交联。金属卟啉或有机敏化剂的可见光照射会产生反应性单线态氧，该单线态氧将胺氧化偶联成亚胺交联键。这种简便的台式交联反应在室温下进行，并在1小时后得到无溶剂的弹性材料。固态¹³C核磁共振和傅立叶变换红外光谱表明，该反应仅产生亚胺官能团，未观察到副产物。使用拉伸实验对这些聚合物的机械性能进行了测试，发现这些聚合物的性能取决于敏化剂的初始负载，在最大测试量下，最大拉伸应变为157％，杨氏模量为2.15 MPa。使用可见光照射，通过该交联系统演示了光刻技术。