The rapid removal of rain droplets at the leaf apex is critical for leaves to avoid damage under rainfall conditions, but the general water drainage principle remains unclear. We demonstrate that the apex structure enhances water drainage on the leaf by employing a curvature-controlled mechanism that is based on shaping a balance between reduced capillarity and enhanced gravity components. The leaf apex shape changes from round to triangle to acuminate, and the leaf surface changes from flat to bent, resulting in the increase of the water drainage rate, high-dripping frequencies, and the reduction of retention volumes. For wet tropical plants, such as Alocasia macrorrhiza, Gaussian curvature reconfiguration at the drip tip leads to the capillarity transition from resistance to actuation, further enhancing water drainage to the largest degree possible. The phenomenon is distinct from the widely researched liquid motion control mechanisms, and it offers a specific parametric approach that can be applied to achieve the desired fluidic behavior in a well-controlled way.

中文翻译：

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顶端结构增强了叶子的排水能力。


叶尖雨滴的快速去除对于叶片避免在降雨条件下受损至关重要，但一般的排水原理仍不清楚。我们证明，顶端结构通过采用曲率控制机制来增强叶子上的排水，该机制基于在减少的毛细管作用和增强的重力分量之间形成平衡。叶尖形状由圆形变为三角形再渐尖，叶面由平坦变为弯曲，导致排水率增加，滴水频率高，滞水量减少。对于湿热带植物，如海芋，滴水尖端的高斯曲率重构导致毛细管作用从阻力到驱动的转变，进一步最大程度地增强排水。这种现象与广泛研究的液体运动控制机制不同，它提供了一种特定的参数方法，可用于以良好控制的方式实现所需的流体行为。