Conventional understanding has it that a liquid deposited on a surface tends to move along directions that reduce surface energy, which is mainly dictated by surface properties rather than liquid properties, such as surface tension. Achieving well-controlled directional steering remains challenging because the liquid-solid interaction mainly occurs in the two-dimensional (2D) domain. We show that the spreading direction of liquids with different surface tensions can be tailored by designing 3D capillary ratchets that create an asymmetric and 3D spreading profile both in and out of the surface plane. Such directional steering is also accompanied by self-propulsion and high flow velocity, all of which are preferred in liquid transport.

中文翻译：

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三维毛细管棘轮诱导的液体定向转向

传统的理解是，沉积在表面上的液体倾向于沿着降低表面能的方向移动，这主要取决于表面特性而不是液体特性，例如表面张力。实现良好控制的方向转向仍然具有挑战性，因为液固相互作用主要发生在二维 (2D) 域中。我们表明，可以通过设计 3D 毛细管棘轮来定制具有不同表面张力的液体的扩散方向，该棘轮在表面平面内外产生不对称和 3D 扩散轮廓。这种定向转向还伴随着自推进和高流速，所有这些都是液体运输的首选。