纳米尺度下润湿的分子动力学模拟  

Understanding wetting at nano scale: Atomistic simulation investigations

作　　者：张晶艳 李晖[1] Jingyan Zhang;Hui Li(International Research Center for Soft Matter,Beijing University of Chemical Technology,Beijing 100029,China)

机构地区：[1]北京化工大学软物质科学与工程高精尖创新中心,北京100029

出　　处：《科学通报》2018年第34期3585-3597,共13页Chinese Science Bulletin

摘　　要：表界面润湿一直是表面科学领域的热门研究课题,了解润湿性和界面结构之间的相关性是研究表面润湿的关键.从经典分子动力学和从头算分子动力学出发,介绍了纳米尺度下的润湿,主要包括以下几方面:(1)原子尺度界面上的润湿;(2)润湿与晶格常数的关系;(3)具有地形表面的范德华(vdW)层状材料的润湿;(4)Wenzel态到Cassie态的转变机理研究;(5)氨基酸侧链疏水性的表征;(6)离子溶剂化的亲憎水性和传输选择性的微观机理.The wetting property of water is crucial in a variety of chemical, biological and technological systems. Finding the relevance between water and the structure of material surface is the key to understand the wettability of water and other implications such as those design nanostructured devices. In those work, we attempt to use the classical and the first-principles molecular dynamics simulations to explore the interactions between water and material surfaces. We have achieved a series of results, mainly including the following aspects:(1) Wettability of graphene and h-BN.(2) Relations between wettability and lattice constant.(3) Wetting of synthesized Bi2Se3. The water contact angle of the ideal Bi2Se3 surface is ~98.4°, and the edge of the terrace on its surface is extremely hydrophilic.(4) Wenzel to Cassie state transition.(5) Characterizing hydrophobicities of amino acid side chains.(6) Hydrophobicity and ion-selectivity. According to these examples, it is found that the molecular dynamics simulation is an extremely important tool to reveal the mechanism of wetting. In wettability of graphene and h-BN, we used Born-Oppenheim quantum molecular dynamics(QMD) simulations and investigated interfacial properties of water droplets on a graphene sheet or a monolayer BN sheet. The QMD simulations reveal that the contact angle of the graphene is 87°, while the contact angle of the monolayer BN sheet is 86°. So they all show weakly hydrophobic. Compared with nanodroplets of water in a supercooled state on the graphene, the results show that under the supercooled condition, water droplets exhibit an appreciably larger contact angle than under the ambient condition. In addition, there are also related introductions about evolution of the interfacial shape in dissolutive wetting and electrowetting. In the relations between wettability and lattice constant, the MD simulation presents a small uniform strain(±3%) applied to the lattice constant of a multilayer hydrophilic surface can generate a marked change in the wetti

关 键 词：水 界面 润湿 第一性原理 分子动力学 

分 类 号：TB383.1[一般工业技术—材料科学与工程]