外电场作用下纳米结构表面润湿转变机理研究  

Wetting Transition on a Hydrophobic Surface With Nano-grooves Under External Electric Field

作　　者：王军[1] 朱星光 张悦 夏国栋[1] WANG Jun;ZHU Xingguang;ZHANG Yue;XIA Guodong(MOE Key Laboratory of Enhanced Heat Transfer and Energy Conservation,Beijing Key Laboratory of Heat Transfer and Energy Conservation,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学传热强化与过程节能教育部重点实验室及传热与能源利用北京市重点实验室,北京100124

出　　处：《北京工业大学学报》2024年第10期1162-1169,共8页Journal of Beijing University of Technology

基　　金：北京市教育委员会青年拔尖人才培养计划资助项目(CIT&TCD201904015)。

摘　　要：采用分子动力学模拟方法,研究了外电场作用下液膜在带有纳米凹槽的疏水表面处由Cassie态向Wenzel态的润湿态转变过程,并分析了其转变机理。结果表明,润湿状态转变所需时长并不随着电场强度的增大而降低,而是存在一个促进润湿状态转变的最佳电场强度。基于电场作用下的液滴润湿角及液柱极化应力的计算分析表明,一方面外电场可以增强表面润湿性,有利于Cassie态向Wenzel态的润湿态转变,另一方面,液膜受电场极化的影响而沿电场方向伸长,从而减缓了液膜向纳米凹槽的渗入。因此,随着电场强度的增大,液膜润湿状态转变时长呈现先减小后增大的趋势。本研究揭示了外电场作用下纳米结构表面的润湿态转变的机理,有助于深入理解微纳米结构表面的电润湿现象。In this paper,the transition from Cassie state to Wenzel state of water film at a hydrophobic surface with a nano-groove under the external electric field was studied by using molecular dynamics(MD)simulation method.It is found that there exists an optimal electric field strength,at which the transition of the wetting state can be promoted.For lower or higher electric field strength,it needs a longer time for the transition of the wetting state.Based on the calculation of the droplet contact angle under the electric field,it is found that the external electric field can enhance the surface wettability,which in turn facilitates the transition from the Cassie state to the Wenzel state.On the other hand,the elongation of the droplet along the electric field direction under the influence of the electric field polarization slows down the infiltration of the droplet into the nano-groove.Therefore,with the increase of electric field intensity,the transition time of liquid film wetting state shows a tendency of decreasing and then increasing after a minimum value.This paper reveals the mechanism of the transition of the wetting state on the surface of nanostructures under the influence of the external electric field,which contributes to a deeper understanding of the electrical wetting phenomenon on the surface with microstructures and nanostructures.

关 键 词：电润湿 润湿态转变 分子动力学模拟 纳米结构表面 接触角 表面润湿性 

分 类 号：TK124[动力工程及工程热物理—工程热物理]