Classical and Ab Initio Molecular Dynamics for Strain-Induced Reactions of 2D Materials: A Coupled Mechanochemistry and Nanotribology Study
Joshua Melendez-Rivera, Texas A&M University
Two-dimensional (2D) layered nanomaterials have been integral to the material technologies used to control friction and wear, as well as drivers for chemical reactions. Since the first isolation of graphene in 2004, various 2D nanomaterials have been discovered and extensively studied due to their unique mechanical, electrical, thermal, and chemical properties. However, at interfaces, localized pressures can create strained regions, leading to material enhancements for chemical reaction applications or a mechanochemically accelerated chemical breakdown of 2D materials. The frictional properties of 2D materials, such as MoS2 and graphene are appealing for use as solid lubricants in various technological applications. However, exposure to environmental species, (e.g. oxygen and water) has been shown to degrade the lubricating properties altering its usefulness for many energy-efficiency applications. To study such effect we will use a combination of Classical Molecular Dynamics simulations (MD), Density Functional Theory Calculations (DFT), and Grand Canonical Monte Carlo (GCMC) simulations via the LAMMPS and Quantum Espresso software packages. Materials will be altered following the elasticity theory versions of Hooke’s law for 2D problem systems: plane stress and plane strain. This approach allows us to manipulate the stress-strain relationship and explore the effects on the frictional and reactive properties of 2D materials, both with and without the presence of other species. Elucidating the precise mechanisms of these interactions is key for improving tribological and mechanochemical performance in said materials.