A new contact model for the discrete element method simulation of TiO2 nanoparticle films undermechanical load

J Laube and V Baric and S Salameh and L Madler and LC Ciacchi, GRANULAR MATTER, 20, 28 (2018).

DOI: 10.1007/s10035-018-0799-9

We develop a novel coarse-grained contact model for Discrete Element Method simulations of TiO2 nanoparticle films subjected to mechanical stress. All model elements and parameters are derived in a self- consistent and physically sound way from all-atom Molecular Dynamics simulations of interacting particles and surfaces. In particular, the nature of atomic-scale friction and dissipation effects is taken into account by explicit modelling of the surface features and water adsorbate layers that strongly mediate the particle-particle interactions. The quantitative accuracy of the coarse-grained model is validated against all-atom simulations of TiO2 nanoparticle agglomerates under tensile stress. Moreover, its predictive power is demonstrated with calculations of force-displacement curves of entire nanoparticle films probed with force spectroscopy. The simulation results are compared with Atomic Force Microscopy and Transmission Electron Microscopy experiments.

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