Computational Biology Center , IBM Thomas J. Watson Research Center , Yorktown Heights , New York 10598 , United States.
J Phys Chem B. 2019 Aug 29;123(34):7243-7252. doi: 10.1021/acs.jpcb.9b02797. Epub 2019 Aug 15.
Water contact angles (WCA) are often used to parametrize force field parameters of novel 2D nanomaterials, such as molybdenum disulfide (MoS), which has emerged as a promising nanomaterial in many biomedical applications due to its unique and impressive properties. However, there is a wide range of water-MoS contact angles in the literature depending on the aging process on the surface of a MoS nanosheet and/or substrate material. In this study, we revisit and optimize existing parameters for the basal plane of MoS with two popular water models, TIP3P and SPC/E, using the wide range of WCAs from various experiments. We develop and deploy the free energy perturbation method for parametrizing MoS with experimentally determined WCAs for both fresh and aged surfaces. Energy decomposition analysis on the simulation trajectories reveals that MoS-water interaction is dominated by van der Waals interaction, which mainly comes from the top layer of MoS. We conclude that to describe both fresh and aged MoS surfaces it is convenient to only adjust the Lennard-Jones parameter ε (the depth of the potential well of a sulfur atom), which displays a surprisingly linear correlation with WCAs.
水接触角（WCA）常用于参数化新型二维纳米材料（如二硫化钼（MoS））的力场参数，由于其独特而令人印象深刻的性质，MoS 在许多生物医学应用中已成为一种很有前途的纳米材料。然而，文献中 MoS 与水的接触角范围很广，这取决于 MoS 纳米片表面和/或基底材料的老化过程。在这项研究中，我们使用各种实验的广泛 WCA 重新审视和优化了用于 MoS 基面的两种流行水模型（TIP3P 和 SPC/E）的现有参数。我们开发并部署了自由能微扰法，使用实验确定的 WCAs 对新鲜和老化表面的 MoS 进行参数化。对模拟轨迹的能量分解分析表明，MoS-水相互作用主要由范德华相互作用主导，主要来自 MoS 的顶层。我们的结论是，为了描述新鲜和老化的 MoS 表面，方便的方法是仅调整 Lennard-Jones 参数ε（硫原子的势能阱深度），它与 WCAs 呈惊人的线性相关。
