论文标题
Marangoni引起的弯月弯曲微量旋转的逆转
Marangoni-Induced Reversal of Meniscus-Climbing Microdroplets
论文作者
论文摘要
小水滴或位于油月板上的小水滴或颗粒通常由于毛细管不平衡而爬上半月板。在这里，我们介绍了这种弯月弯曲行为的尺寸依赖性逆转，在冷却下面的底物后，不同尺寸的液滴同时上升并下降了半月板。我们表明，微弯面板中的微观marangoni对流细胞是该现象的原因。虽然相对较大的水微动物的动力学仍然由不平衡的毛细管力支配，因此沿弯月板上升高，但较小的液滴由表面流动，因此降低了半月板。我们进一步证明，对流单元的大小和方向取决于半月板几何形状和底物温度，并引入了一个改良的Marangoni数，可以很好地预测它们的强度。我们的发现为操纵液滴的液滴提供了一种新方法，该液滴可能在材料自组装，生物学敏感的感测和测试或相变热传播中应用。
Small water droplets or particles located at an oil meniscus typically climb the meniscus due to unbalanced capillary forces. Here, we introduce a size-dependent reversal of this meniscus-climbing behavior, where upon cooling of the underlying substrate, droplets of different sizes concurrently ascend and descend the meniscus. We show that microscopic Marangoni convection cells within the oil meniscus are responsible for this phenomenon. While dynamics of relatively larger water microdroplets are still dominated by unbalanced capillary forces and hence ascend the meniscus, smaller droplets are carried by the surface flow and consequently descend the meniscus. We further demonstrate that the magnitude and direction of the convection cells depend on the meniscus geometry and the substrate temperature and introduce a modified Marangoni number that well predicts their strength. Our findings provide a new approach to manipulating droplets on a liquid meniscus that could have applications in material self-assembly, biological sensitive sensing and testing, or phase change heat transfer.
