液滴在双轨亲水轨道上的运动特性研究

目的 探究重力驱动液滴在双轨亲水轨道上的运动特性，揭示其力学机理。方法 采用喷涂法制备不锈钢超疏水表面，然后采用激光刻蚀法在超疏水表面上加工出不同类型的亲水轨道。研究液滴在不同轨道上的运动行为，讨论液滴运动状态与轨道参数之间的关系，并对液滴运动的力学特性进行分析。结果 液滴在平行双轨轨道上的运动阻力约为在单轨轨道上的1.6~2.4倍，其与轨道宽度呈正相关，与轨道间距呈负相关，且液滴运动终止时呈现出轨道中途停滞、轨道末端停滞、脱离轨道末端三种状态;液滴在非平行双轨轨道上的运动阻力与运动方向有关，由宽端至窄端的运动阻力较由窄端至宽端更小，前者约为后者的90.7%。结论 液滴在轨道上的运动阻力主要受液滴与亲水轨道的接触面积影响。当平行双轨轨道的间距增大时，液滴在垂直轨道的方向上拉伸效果增强，液滴将沿平行轨道的方向收缩，铺展长度减小，由此液滴与亲水轨道的接触面积减小，从而降低了液滴运动阻力;而液滴在非平行轨道不同运动方向上的阻力差异与液滴的表面张力有关。

Motion Characteristics Study of Water Droplets on Dual-rail Hydrophilic Tracks

Inspired by the dual-rail tracks train, the motion characteristics of water droplets on the dual-rail hydrophilic tracks was studied, and its mechanical mechanism was revealed. First, the superhydrophobic surface of stainless steel was prepared by spraying method, and then different types of hydrophilic tracks were processed on the superhydrophobic surface by laser etching. The motion behavior of water droplets on different tracks was studied, the relationship between water droplets motion state and tracks parameters was discussed, and the mechanical properties of water droplets motion was analyzed. The results show that the movement resistance of water droplets on the parallel dual-rail tracks is about 1.6-2.4 times that of the single track, and is positively correlated with tracks width and negatively correlated with tracks spacing. The termination state of water droplets movement presents three types:stagnation in the middle of the tracks, stagnation at the end of the tracks and separation from the end of the tracks. The movement resistance of water droplets on non-parallel dual-rail tracks is related to the movement direction, and the movement resistance from wide end to narrow end is smaller than that from narrow end to wide end, which is about 90.7% of latter. It is concluded that the movement resistance of water droplets on the tracks is mainly affected by the contact area between water droplets and hydrophilic tracks. When the spacing of parallel dual-rail tracks increases, the stretching effect of water droplets in the vertical tracks direction will enhanced, then the water droplets will shrink along the parallel tracks direction and the spreading length will decrease, so the contact area between water droplets and hydrophilic tracks decreases, which lead to the movement resistance of water droplets reduced. However, the resistance difference of water droplets in different directions of non-parallel tracks is related to the surface tension of water droplets.