There are currently three main classes of liquid-repellent surfaces: micro- or nanostructured superhydrophobic surfaces, flat surfaces grafted with “liquidlike” polymer brushes, and lubricated surfaces. Despite recent progress, the mechanistic explanation for the differences in droplet behavior on such surfaces is still under debate. Here, we measure the dissipative force acting on a droplet moving on representatives of these surfaces at different velocities $U=0.01–1\mathrm{mm}/\mathrm{s}$ using a cantilever force sensor with submicronewton accuracy and correlate it to the contact line dynamics observed using optical interferometry at high spatial (micron) and temporal ($<0.1\mathrm{s}$) resolutions. We find that the dissipative force—due to very different physical mechanisms at the contact line—is independent of velocity on superhydrophobic surfaces but depends nonlinearly on velocity for flat and lubricated surfaces. The techniques and insights presented here will inform future work on liquid-repellent surfaces and enable their rational design.

中文翻译：

---

在结构化，平坦和润滑的疏水表面上具有极高的拒液性的起源

当前存在三种主要的拒液表面：微或纳米结构的超疏水表面，接有“类液体”聚合物刷的平坦表面和润滑表面。尽管有最新进展，但对于这种表面上液滴行为差异的机理解释仍在争论中。在这里，我们测量了以不同的速度作用在这些表面的代表上运动的液滴上的耗散力$ü=0.01–\mathrm{1个}\mathrm{毫米}/\mathrm{s}$ 使用具有亚微牛顿精度的悬臂力传感器，并将其与使用光学干涉术在高空间（微米）和时空（$<0.1\mathrm{s}$）决议。我们发现，由于接触线处的物理机制非常不同，耗散力与超疏水表面的速度无关，而与平坦和润滑表面的速度非线性相关。此处介绍的技术和见解将为防液表面的未来工作提供参考，并使其合理设计成为可能。