液滴冲击固体表面的现象普遍存在且充分体现着流体力学之美。这一经典现象蕴含着丰富的物理内涵，其标志性体现是多尺度微纳气膜结构的形成。液滴接近壁面约几微米时所形成的气膜粘性效应突显，同时引入了跨度达一万倍的多重特征尺度和气-液-固相互作用及界面失稳。带电液滴在云层雷电产生、汽车喷漆、静电喷雾和农作物植保方面都扮演重要角色。液体表面由于电荷引起静电应力可能改变液滴表面曲率并对气膜结构和飞溅现象产生根本性的改变。目前的研究虽然分别在中性液滴冲击平板与自由液体表面在静电场下的变形有较深入的研究，但未能将二者结合起来，缺乏对带电液滴冲击平板形成的微纳尺度气膜结构的定量测量，缺乏准确描述气膜结构的演变机制模型。本项目拟系统地研究带电液滴冲击平板气膜结构动态演变和润湿冲击动力学。研究所获得的结果可为喷涂、雾化冷却、3D打印、农作物植保、材料沉积等领域提供新的应用思路。

The impact of liquid droplets on solid surface is a ubiquitous and beautiful phenomenon of fluid dynamics. This classic event has rich physical implications, and the hallmark is the formation of the multiscale gas film upon impact. Immediately prior to the impact, the thickness of the gas layer between the bottom of the droplet and the solid surface is sufficiently thin (on the order of micrometers) that the viscous effect is important and a creeping flow of gas is formed. This introduces multiple characteristic lengths range spanning four orders of magnitude, as well as the instability at the gas-liquid-sold interface. On the other hand, charged droplets play important roles in thunder and storms, exterior painting of automobiles, and electrospray deposition of functional materials. The electric stress at the droplet surface may alter the droplet curvature, change the gas film structure and subsequent flash. Existing researches have made extensive yet separate study on neutral droplet impact and deformation of free liquid surface under intense electric fields, few considered the collective effect of those two factors. Also there is a lack of quantitative measurement of the micro/nano gas film structure and a precise description of the gas film evolution of charged droplets impacting on solid surfaces. This project aims to systematically study the impact dynamics of the charged droplets on smooth solid surfaces. The results obtained from this research will shed light on numerous application areas including spray coating, spray cooling, 3D printing, agriculture protection, and material depositions.