Heier Michaela, Stephan Simon, Diewald Felix, Müller Ralf, Langenbach Kai, Hasse Hans
Laboratory of Engineering Thermodynamics, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany.
Institute of Applied Mechanics, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany.
Langmuir. 2021 Jun 22;37(24):7405-7419. doi: 10.1021/acs.langmuir.1c00780. Epub 2021 Jun 7.
The wetting of surfaces is strongly influenced by adsorbate layers. Therefore, in this work, sessile drops and their interaction with adsorbate layers on surfaces were investigated by molecular dynamics simulations. Binary fluid model mixtures were considered. The two components of the fluid mixture have the same pure component parameters, but one component has a stronger and the other a weaker affinity to the surface. Furthermore, the unlike interactions between both components were varied. All interactions were described by the Lennard-Jones truncated and shifted potential with a cutoff radius of 2.5σ. The simulations were carried out at constant temperature for mixtures of different compositions. The parameters were varied systematically and chosen such that cases with partial wetting as well as cases with total wetting were obtained and the relation between the varied molecular parameters and the phenomenological behavior was elucidated. Data on the contact angle as well as on the mole fraction and thickness of the adsorbate layer were obtained, accompanied by information on liquid and gaseous bulk phases and the corresponding phase equilibrium. Also, the influence of the adsorbate layer on the wetting was studied: for a sufficiently thick adsorbate layer, the wall's influence on the wetting vanishes, which is then only determined by the adsorbate layer.
表面的润湿性受到吸附层的强烈影响。因此，在本工作中，通过分子动力学模拟研究了固着液滴及其与表面吸附层的相互作用。考虑了二元流体模型混合物。流体混合物的两个组分具有相同的纯组分参数，但其中一个组分对表面的亲和力较强，另一个较弱。此外，两种组分之间的异类相互作用是变化的。所有相互作用均采用截断和位移的 Lennard-Jones 势描述，截止半径为 2.5σ。在恒定温度下对不同组成的混合物进行模拟。系统地改变参数并进行选择，以便获得部分润湿和完全润湿的情况，并阐明变化的分子参数与现象学行为之间的关系。获得了接触角以及吸附层的摩尔分数和厚度的数据，同时还有关于液相和气相本体相以及相应相平衡的信息。此外，还研究了吸附层对润湿性的影响：对于足够厚的吸附层，壁对润湿性的影响消失，此时润湿性仅由吸附层决定。
