Abstract In this study, classic Molecular Dynamics (MD) simulations with established force fields were first performed to investigate the salinity effects on the static contact angle of a n-decane droplet immersing in water atmosphere within a calcite nanochannel to advance our microscopic understanding on low salinity flooding. By applying an external body force, dynamic contact angle of n-decane in water phase was also studied in the presence of various salt concentrations based on Non-Equilibrium MD simulation. The predicted n-decane static contact angles are around 59.68° ± 0.26°, which agree well with experimental results in previous studies. A reduction of the static contact angle of the nanodrop is observed with the increase of salinity, which implies an enhancement of surface hydrophilicity. Under flow conditions, the deformation of nanodrop, as evidenced by the centre of mass analysis, becomes faster by increasing the salt concentration. The recovery/mobility of the n-decane nanodrop is, however, still significantly restricted by the adsorption interaction between the substrate and n-decane phase, which may lead to droplet snapping off and/or breaking up into small droplets.

中文翻译：

---

油/盐水/方解石系统中静态和动态接触角的盐度依赖性变化：分子动力学模拟研究

摘要 在这项研究中，首先进行了具有已建立力场的经典分子动力学 (MD) 模拟，以研究盐度对浸入方解石纳米通道内水气氛中的正癸烷液滴的静态接触角的影响，以促进我们对低浓度的微观理解。盐度泛滥。通过施加外部体力，还基于非平衡 MD 模拟研究了在各种盐浓度存在下水相中正癸烷的动态接触角。预测的正癸烷静态接触角约为 59.68°±0.26°，这与先前研究中的实验结果非常吻合。随着盐度的增加，观察到纳米滴的静态接触角减小，这意味着表面亲水性的增强。在流动条件下，正如质量中心分析所证明的那样，随着盐浓度的增加，纳米滴的变形变得更快。然而，正癸烷纳米滴的回收/流动性仍然受到基材和正癸烷相之间的吸附相互作用的显着限制，这可能导致液滴折断和/或分解成小液滴。