Introduction of hierarchical microstructures nowadays is considered as an important method to create superhydrophobic surfaces, but the majority of current studies mainly focus on arbitrary or simple 3D geometries. Therefore, only statistic results or particular conclusions can be obtained. Given this concern, two‐photon polymerization (TPP) is applied to create well‐defined 3D microstructures with high resolution, including fractal Sierpinski tetrahedrons, and hierarchical pyramid structures. Surfaces that have fractal structures with higher complexity are found to be more hydrophobic than their lower‐stage counterparts. Additionally, fractal Sierpinski tetrahedron structures prove to possess higher efficiency in achieving superhydrophobicity when compared to hierarchical pyramids. Further, TPP is also adopted in creating microstructures on flexible substrates. As a demonstration, an array of hierarchical pyramids is fabricated on a plastic film, and superhydrophobicity still remains even after 100 times of bending and relaxing. Moreover, owing to the convenience of spatial control from TPP, tuning of wetting performance in different regions of surfaces is achievable. With this technique, the role of the fractal and hierarchical microstructures in flexible natural creatures can be better understood, thus facilitating the applications, for which robust wetting control is required.

中文翻译：

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基于分形和层级微结构的双光子聚合超疏水表面：柔性超疏水膜

如今，引入分层微结构被认为是创建超疏水表面的重要方法，但是当前的大多数研究主要集中于任意或简单的3D几何形状。因此，只能获得统计结果或特定结论。考虑到这一点，采用了两光子聚合（TPP）来创建具有高分辨率的清晰3D微结构，包括分形Sierpinski四面体和分层金字塔结构。分形结构具有较高复杂性的表面比其较低级的表面具有更大的疏水性。另外，与分层金字塔相比，分形Sierpinski四面体结构在实现超疏水性方面具有更高的效率。进一步，TPP还用于在柔性基板上创建微结构。作为演示，在塑料薄膜上制造了一系列分层的金字塔，即使经过100次弯曲和松弛后，超疏水性仍然保持。而且，由于来自TPP的空间控制的便利性，可以实现表面不同区域的润湿性能的调整。使用这种技术，可以更好地理解分形和层次微结构在柔性自然生物中的作用，从而简化了需要强大的润湿控制的应用。可以调节表面不同区域的润湿性能。使用这种技术，可以更好地理解分形和层次微结构在柔性自然生物中的作用，从而简化了需要强大的润湿控制的应用。可以调节表面不同区域的润湿性能。使用这种技术，可以更好地理解分形和层次微结构在柔性自然生物中的作用，从而简化了需要强大的润湿控制的应用。