Manipulating droplets by tailoring the surface wettability has recently attracted a great interest of research. In this work, controllable splitting of impacting droplets was realized by a hybrid-wettability surface consisting of a hydrophilic background surface and two intersecting hydrophobic stripes. A three-dimensional VOF-based (volume of fluid) numerical model had been developed to investigate the splitting dynamics, and a dynamic contact angle model had been employed to capture the droplet interface near the triple line. Several key parameters including surface hydrophilicity, stripe hydrophobicity, stripe width, and impact Weber number were examined. On the basis of these parameters, complete impact phase diagrams were constructed. The results showed that there are four possible pathways for impacting droplets, namely no splitting I, no splitting II, splitting I, and splitting II. The conditions for the four pathways were distinguished. Finally, some new methods had been proposed to further control volume ratios of split satellite droplets and splitting time. The results reported in this work provided useful guideline for designing hybrid-wettability surfaces to realize controllable droplet splitting.

通过调整表面润湿性来操纵液滴最近引起了极大的研究兴趣。在这项工作中，通过由亲水性背景表面和两个相交的疏水性条纹组成的混合可润湿性表面，实现了对可控液滴的可控分裂。建立了基于三维VOF的（流体体积）数值模型来研究分裂动力学，并采用了动态接触角模型来捕获三线附近的液滴界面。检查了几个关键参数，包括表面亲水性，条纹疏水性，条纹宽度和冲击韦伯数。基于这些参数，构建了完整的碰撞阶段图。结果表明，影响液滴的途径有四种，即无分裂I，不拆分II，拆分I和拆分II。区分了这四个途径的条件。最后，提出了一些新的方法来进一步控制分裂卫星液滴的体积比和分裂时间。这项工作中报告的结果为设计混合润湿性表面以实现可控的液滴分裂提供了有用的指导。