(195h) Force Field for Molybdenum Disulfide to Compute Bulk and Interfacial Properties with Electrolytes and Biomacromolecules in High Accuracy

Authors: 
Liu, J., University of Colorado Boulder
Zeng, J., University of Colorado Boulder
Wang, Z., University of Colorado Boulder
Chen, J., University of Washington
De Yoreo, J. J., Pacific Northwest National Laboratory
Huang, Y., University of California Los Angeles
Heinz, H., University of Colorado Boulder
Molybdenum disulfide (MoS2) is a layered material with outstanding electrical and optical properties. Numerous studies evaluate the performance in sensors, catalysts, and batteries that may benefit from guidance by simulations in all-atom resolution. In this paper we present parameters for MoS2 that extend the Interface force field and are compatible with many platforms for molecular simulations (CVFF, PCFF, CHARMM, AMBER, OPLS-AA). The parameters reproduce X-structure, infrared spectrum, bulk modulus, Young’s modulus, and aqueous interfacial properties using atomic charges in agreement with internal multipole moments and van-der-Waals parameters for dispersion interactions. For example, the computed water contact angle is 69.2±4.1°, the experimental measurement water contact angle on fresh MoS2 surface is 69±3.8°. The computed diiodomethane contact angle is 14.7±1.6°, the average experimental data is 15.2°. We applied the model to elucidate the binding mechanism and free energy of adsorption of peptides on the MoS2 basal plane in excellent agreement with the experimental observations using strongly binding sequences derived from phage display and weakly binding control sequences. Water molecules are only weakly bound to the MoS2 surface and peptide adsorption is driven by depletion interactions whereby the peptide from solution replaces surface bound water and no longer disrupts the hydrogen bonded network of water. The model is applicable to any MoS2-based biomaterials and nanomaterials as part of IFF and can be extended for reactive simulations.
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