Parameterization of Molybdenum Disulfide Interacting with Water Using the Free Energy Perturbation Method

Abstract

Water contact angles (WCA) are often used to parametrize force field parameters of novel 2D nanomaterials, such as molybdenum disulfide (MoS2), 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–MoS2 contact angles in the literature depending on the aging process on the surface of a MoS2 nanosheet and/or substrate material. In this study, we revisit and optimize existing parameters for the basal plane of MoS2 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 MoS2 with experimentally determined WCAs for both fresh and aged surfaces. Energy decomposition analysis on the simulation trajectories reveals that MoS2–water interaction is dominated by van der Waals interaction, which mainly comes from the top layer of MoS2. We conclude that to describe both fresh and aged MoS2 surfaces it is convenient to only adjust the Lennard-Jones parameter εS (the depth of the potential well of a sulfur atom), which displays a surprisingly linear correlation with WCAs.

Interpretable molecular models for molybdenum disulfide and insight into selective peptide recognition

“…Earlier computational studies of the contact angle also involved tuned interaction parameters to match contact angles of fresh and aged MoS 2 surfaces, 86 however, in this approach the chemical changes to the surface such as contamination by airborne hydrocarbons or oxidation are not considered. 65 In our approach, the interaction parameters have a clear rationale, do not require customized ts to reproduce contact angles, and changes in surface chemistry can be explicitly included.…”

Membrane Insertion of MoS2Nanosheets: Fresh vs. Aged

“…Here, we applied the MD simulations to investigate the interactions of fresh and aged MoS 2 nanosheets with POPE lipid membrane. In order to efficiently model both fresh and aged MoS 2 surfaces, we have developed a simplified model by only adjusting the Lennard-Jones parameter, ε S, (the depth of the potential well of a sulfur atom) 17 , which demonstrates a surprisingly linear relationship between the ε S and water contact angle (WCA). In this study, the surface-aging dependent interaction of a MoS 2 nanosheet with membranes can thus be "achieved" using this simple MoS 2 force field model.…”

“…In this study, the surface-aging dependent interaction of a MoS 2 nanosheet with membranes can thus be "achieved" using this simple MoS 2 force field model. [17][18] Table 1 lists two sets of force field parameters for the fresh and aged MoS 2 nanosheets, respectively.…”

“…22 The force field parameters of the fresh and aged MoS 2 nanosheets were employed based on our previous works. [17][18] The CHARMM 36 force field [23][24][25] and TIP3P water model 26 were adopted for POPE molecules and water molecules, respectively. Following similar protocols in our previous studies [27][28][29][30][31][32][33] , periodic boundary conditions of these systems were treated in all directions (x y and z).…”

“…Table 1．Forcefield parameters for the fresh and aged MoS 2 nanosheets, respectively. (Derived from our previous work[17][18] ) The simulation model of MoS 2 nanosheet on the POPE lipid membrane in a water box. Molybdenum and sulfur atoms are displayed by pink and yellow spheres, respectively.…”