Numerous organisms exploit asymmetrical capillary forces generated by unique fiber or asymmetrical tapered structures to rapidly eliminate undesired liquid for survival in moist or rainy habitats. Human eyelashes, the primary protector of eyes, use a yet-to-be-fully-understood mechanism to efficiently transfer incoming liquid for vision safeguarding. Here, we elucidate that human eyelashes featuring a hydrophobic curved flexible fiber array with surface micro-ratchet and macro-curvature approximating the Brachistochrone is adept at directionally and rapidly expelling incoming liquid to maintain clear vision. These structural attributes are sequentially used for liquid drainage, starting from anisotropic retention via micro-ratchet, followed by the elastic expulsion among deflected hydrophobic flexible fiber arrays and culminating in the fastest sliding off along a Brachistochrone path, which together reduce the contact time by about 20% of that on rigid linear slopes. Investigating the intricate relationship between multistructure and draining efficiency of human eyelashes may inspire the design of advanced liquid-repelling edges on outdoor devices to maintain dryness.

中文翻译：

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疏水性 Brachistochrone 纤维阵列的人睫毛上的快速排水


许多生物体利用由独特纤维或不对称锥形结构产生的不对称毛细管力来快速消除不需要的液体，以便在潮湿或多雨的栖息地中生存。人的睫毛是眼睛的主要保护者，它使用一种尚未完全理解的机制来有效地转移进入的液体以保护视力。在这里，我们阐明了人类睫毛具有疏水性弯曲柔性纤维阵列，表面微棘轮和近似 Brachistochrone 的宏观曲率擅长定向和快速排出进入的液体以保持清晰的视力。这些结构属性依次用于液体排放，从通过微棘轮的各向异性保留开始，然后是偏转的疏水柔性纤维阵列之间的弹性排出，最后是沿 Brachistochrone 路径的最快滑动，它们共同减少了约 20% 的接触时间在刚性线性斜坡上。研究人类睫毛的多结构和排水效率之间的复杂关系可能会激发在户外设备上设计先进的排液边缘以保持干燥。