On the Mechanisms of Coalescence of Nanodroplets and Sintering of Solid Particles

The droplet coalescence theory, which implies the refinement and further development of the Frenkel approach, has, for the first time, been used for predicting the characteristic time of coalescence of nanodroplets. The coalescence times obtained for gold nanodroplets agree, in the order of magnitude, with the results of our molecular-dynamics experiments. In addition, the characteristic times of coalescence have been evaluated theoretically for macroscopic droplets of epoxy resin. The results obtained are in good agreement with Geguzin’s experimental data. It has been concluded that the viscous flows arising in coalescing droplets and the corresponding dissipation of the surface free energy underlie the coalescence mechanism of not only macroscopic, but also nanosized droplets. At the same time, the results of our molecular-dynamics calculations and available experimental data indicate that the sintering of crystalline nanoparticles cannot be explained by the Frenkel mechanism of solid body viscous flow.