Molecular Dynamics Study of Adsorption and Wetting of Mixtures of Simple Fluids on Planar Walls

The influence of molecular interactions on the adsorption and wetting of binary mixtures was studied by molecular dynamics simulations of sessile droplets on planar walls. The results provide insights into the competing effects between the fluid–fluid interactions and the solid–fluid interactions on the adsorption and wetting of mixtures. All interactions were modeled by the Lennard-Jones truncated–shifted (LJTS) potential. The influence of the different dispersive interactions in the fluid mixture as well as those between the fluid components and the wall on the gas and liquid adsorption, the three-phase contact, and the contact angle was determined. For the fluid mixtures studied in the present work, the phase behavior and the vapor–liquid interfacial properties are known from recent studies. Together with the present results, this provides a comprehensive picture of the influence of different molecular interactions on the closely related phenomena of wetting and adsorption in mixtures.本研究通过对平面壁面上的固着液滴开展分子动力学模拟，探究了分子间相互作用对二元混合物吸附与润湿行为的影响。研究结果阐明了流体-流体相互作用与固体-流体相互作用之间的竞争效应对混合物吸附与润湿过程的调控机制。所有分子间相互作用均采用截断移位伦纳德-琼斯势（Lennard-Jones Truncated-Shifted, LJTS）进行建模。本工作明确了流体混合物内部不同色散相互作用，以及流体组分与壁面之间的色散相互作用，对气液吸附、三相接触及接触角的影响规律。对于本研究涉及的流体混合物，其相行为与气液界面性质已在近期相关研究中得到充分表征。结合本次研究结果，可全面阐明不同分子间相互作用对混合物中润湿与吸附这两类密切相关现象的影响机制，构建起完整的认知图景。