Dynamics of nanoparticle adhesion

Jan Michael Y. Carrillo, Andrey V. Dobrynin

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

We performed molecular dynamics simulations and theoretical analysis of nanoparticle pulling off from adhesive substrates. Our theoretical model of nanoparticle detachment is based on the Kramers solution of the stochastic barrier crossing in effective one-dimensional potential well. The activation energy, ΔE, for nanoparticle detachment first decreases linearly with increasing the magnitude of the applied force, f, then it follows a power law ΔE (f* - f)3/2 as magnitude of the pulling force f approaches a critical detachment force value, f. These two different regimes in activation energy dependence on magnitude of the applied force are confirmed by analyzing nanoparticle detachment in effective one-dimensional potential obtained by weighted histogram analysis method. Simulations show that detachment of nanoparticle proceeds through neck formation such that magnitude of the activation energy is determined by balancing surface energy of the neck connecting particle to a substrate with elastic energy of nanoparticle deformation. In this regime the activation energy at zero applied force, ΔE0, for nanoparticle with radius, Rp, shear modulus, G, surface energy, γp, and work of adhesion, W, is a universal function of the dimensionless parameter δ γ pW-23(GRp)-13. Simulation data are described by a scaling function ΔE0γp 5/2Rp1/2G-3/2δ-3.75. Molecular dynamics simulations of nanoparticle detachment show that the Kramers approach fails in the vicinity of the critical detachment force f where activation energy barrier becomes smaller than the thermal energy kBT. In the interval of the pulling forces f > f nanoparticle detachment becomes a deterministic process.

Original languageEnglish
Article number214902
JournalJournal of Chemical Physics
Volume137
Issue number21
DOIs
StatePublished - Dec 7 2012
Externally publishedYes

Funding

This work was supported by the National Science Foundation under the Grant DMR-1004576 and by the Petroleum Research Fund of the American Chemical Society under Grant No. PRF#49866ND.

FundersFunder number
National Science FoundationDMR-1004576
American Chemical Society Petroleum Research Fund49866ND

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