液滴在纳米构型表面润湿模式转变机制的分子动力学模拟  

Molecular dynamics simulation of droplet wetting mode transformation mechanism on nanostructured surface

作　　者：郑佳杰 李玉秀 郑丹菁 孔令辉 谢驰 陈颖 ZHENG Jiajie;LI Yuxiu;ZHENG Danjing;KONG Linghui;XIE Chi;CHEN Ying(School of Materials and Energy,Guangdong University of Technology,Guangzhou 510006,Guangdong,China)

机构地区：[1]广东工业大学材料与能源学院,广东广州510006

出　　处：《能源化工》2024年第5期31-38,共8页Energy Chemical Industry

基　　金：国家自然科学基金项目(51776043);国家自然科学基金项目(U20A20299)。

摘　　要：为了得到在分子水平上定量认识润湿性的转变规律和机理,采用正向通量采样高级采样方法,有效解决了直接分子动力学模拟在采样稀有事件时存在时间尺度分离的问题,观察到了不同固液相互作用强度下的液滴在倒三角形纳米构型表面的润湿态由Cassie态到Wenzel态转变的全过程。模拟结果表明,随着固液相互作用强度的增大,液滴润湿模式转变存在2种机制。一种是在固液弱相互作用下,固液接触线始终钉扎在矩形纳米凸起结构折角线处,液滴在纳米沟槽内局部曲面下探变形;另一种是在稍强的固液相互作用下,固液接触线沿着纳米沟槽内壁面下移,沟槽内部的曲面保持原有的平滑曲面边界。研究所得的润湿机制有助于提高超疏水表面的稳定性,为设计制造超疏水纳米构型表面提供指导。To obtain a quantitative understanding of the transformation rules and mechanisms of wettability at the molecular level,an advanced sampling method of forward flux sampling is adopted to effectively solve the problem of time scale separation in direct molecular dynamics simulations for sampling rare events.The entire process of the wettability transition of droplets from Cassie state to Wenzel state on inverted triangular nanostructured surfaces with different solid-liquid interaction strengths is observed.The simulation results show that there are two mechanisms for the wettability mode transition with increasing solid-liquid interaction strength.One is that under weak solid-liquid interactions,the solid-liquid contact line is always pinned at the corner line of the rectangular nanoparticle protrusion structure,and the droplet deforms locally in the nanogroove under the curved surface.Another approach is that under slightly stronger solid-liquid interactions,the solid-liquid contact line moves downward along the inner wall of the nanogroove,and the curved surface inside the groove maintains its original smooth boundary.The wettability mechanisms obtained from research can help improve the stability of superhydrophobic surfaces and provide guidance for designing and manufacturing superhydrophobic nanostructured surfaces.

关 键 词：纳米构型表面 润湿性转变 自由能 增强采样 分子动力学模拟 

分 类 号：O552.4[理学—热学与物质分子运动论]