Two‐photon printing is accomplished using a photobase generator, 2‐(2‐nitrophenyl)‐propyloxycarbony tetramethyl guanidine, to locally catalyze thiol‐ene coupling between multifunctional monomers while mitigating chain‐growth polymerization with free radical scavengers. Microstructures printed from base‐catalyzed resins exhibit higher resolution (linewidths < 400 nm) and lower print error (<3%) than analogous microstructures printed using a photosensitive, free radical initiator. Further, Raman spectroscopy reveals that resins polymerized using the photobase generator in the presence of free radical scavengers exhibit higher selectivity of thiol‐ene coupling over radical polymerization, resulting in stiffer, more uniform polymer networks. The base‐catalyzed resins are capable of producing 3D microstructures printed with high accuracy and minimal post‐processing defects. A direct comparison between free radical and base‐initiated resins highlights the need for mindful consideration of how chemical reaction pathway influences printability and network end‐properties when designing resins.

中文翻译：

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涉及硫醇-迈克尔网络形成的碱催化树脂的双光子打印

双光子印刷是使用光产碱剂2-(2-硝基苯基)-丙氧羰基四甲基胍来完成的，局部催化多官能单体之间的硫醇-烯偶联，同时用自由基清除剂减轻链增长聚合。与使用光敏自由基引发剂打印的类似微结构相比，由碱催化树脂打印的微结构具有更高的分辨率（线宽< 400 nm）和更低的打印误差（<3%）。此外，拉曼光谱表明，在自由基清除剂存在下使用光产碱剂聚合的树脂表现出比自由基聚合更高的硫醇-烯偶联选择性，从而产生更硬、更均匀的聚合物网络。碱催化树脂能够打印出高精度的 3D 微结构，并将后处理缺陷降至最低。自由基和碱引发树脂之间的直接比较凸显了在设计树脂时需要认真考虑化学反应途径如何影响可印刷性和网络末端性能。