This work presents self-focusing 3D lithography based on the refractive index changes of polyethylene glycol diacrylate (PEGDA) during photopolymerization. Since the polymerization of PEGDA leads to an increase in the refractive index, the UV light rays in the PEGDA undergo a refraction effect during exposure, thus being focused and forming 3D photopolymerized structures. We demonstrate the potential of self-focusing 3D lithography by fabricating PEGDA microneedles and trapezoid-shaped microwells. Their structures well match our theoretical estimation. Therefore, our theoretical approach can provide a short route to realizing on-demand, complicated 3D structures of refractive-index-variable materials with single UV exposure.

中文翻译：

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具有不同折射率 PEGDA 的自聚焦 3D 光刻

这项工作提出了基于聚乙二醇二丙烯酸酯 (PEGDA) 在光聚合过程中折射率变化的自聚焦 3D 光刻。由于PEGDA的聚合导致折射率增加，PEGDA中的紫外线在曝光时会发生折射效应，从而被聚焦并形成3D光聚合结构。我们通过制造 PEGDA 微针和梯形微孔来展示自聚焦 3D 光刻的潜力。它们的结构非常符合我们的理论估计。因此，我们的理论方法可以提供一条捷径，以通过单次紫外线照射实现按需、复杂的折射率可变材料 3D 结构。