This work experimentally investigated the water droplet impingement behaviors on carbon nanotube (CNT) array surfaces characterized by different wettabilities from hydrophilicity to superhydrophobicity. By varying the impact velocity, six typical dynamic behaviors of droplet impact were identified and a related droplet regime map was developed under different wettabilities. To further investigate the evolution behavior of droplet impact, the dynamic contact angle (DCA) and spreading factor were measured and analyzed. The damped oscillations of DCA were observed for wettable and mildly hydrophobic CNT array surfaces, while the approximate impact inertia independence was verified for high hydrophobicity or even superhydrophobicity. The contact line velocity in the vicinity of triple phase interface was found to be highly related to the DCA variation at the initial stage of spreading. The discrepancy of DCA on different wettable surfaces reduced significantly with the increase of Weber number. The reduction in post-impact CAs and resultant wettability enhancement after droplet impingement was mainly attributed to self-assembly structures caused by the capillary action during the spreading phase.

这项工作实验研究了水滴在碳纳米管（CNT）阵列表面的撞击行为，其特征是从亲水性到超疏水性的​​不同​​润湿性。通过改变冲击速度，确定了液滴冲击的六个典型动态行为，并在不同的润湿性下建立了相关的液滴状态图。为了进一步研究液滴冲击的演化行为，对动态接触角（DCA）和扩散因子进行了测量和分析。对于可湿性和中等疏水性的CNT阵列表面，观察到DCA的阻尼振荡，而对于高疏水性甚至超疏水性，验证了近似的冲击惯性独立性。发现在扩展初始阶段，三相界面附近的接触线速度与DCA的变化高度相关。随着韦伯数的增加，不同可湿性表面上DCA的差异显着降低。液滴撞击后，撞击后CA的减少和可润湿性的提高主要归因于铺展阶段毛细作用引起的自组装结构。