Detachment of nanoparticles from a substrate is studied by using molecular dynamics simulations. The critical detachment force, f*, is obtained as a function of the nanoparticle radius, Rp, shear modulus, G, surface energy, ?p, and work of adhesion, W. The magnitude of the detachment force is shown to increase from pWRpto 2.2pWRp with increasing nanoparticle shear modulus and nanoparticle size. This variation of the detachment force is a manifestation of a neck formation upon nanoparticle detachment. Using scaling analysis, we show that the magnitude of the detachment force is controlled by the balance of the nanoparticle elastic energy, surface energy of the neck, and nanoparticle adhesion energy to a substrate. It is a function of the dimensionless parameter d~?p(GRp)-1/3W-2/3which is proportional to the ratio of the surface energy of a neck and the elastic energy of deformed nanoparticle. In the case of small values of the parameter d<>1, the critical detachment force, f*, scales as f* ~ ?p3/2Rp1/2G-1/2. Simulation data are in good qualitative agreement with scaling results.

Contact mechanics of nanoparticles: Molecular dynamics simulations

248th National Meeting (2014)

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