Volume 7, No. 3, September 2007, Pages 278-303 PDF(916 KB)
Molecular Dynamics Study of Nanoparticle Collision with a Surface – Implication to Nanoparticle Filtration
Shintaro Sato1, Da-Ren Chen2, David Y. H. Pui1
1 Particle Technology Laboratory, Mechanical Engineering Department, University of Minnesota, 111 Church St. SE, Minneapolis, MN 55455, USA.
2 Department of Mechanical Engineering, Join Program in Environmental Engineering Science, Washington University in St. Louis, St. Louis, MO 63141, USA.
Collision dynamics of nanoparticles with a surface was studied by classical molecular dynamics simulations. Silver, nickel and silica were selected as the particle materials, and silver as the surface material. Particle sizes ranged approximately from 0.5 to 2 nm. The results indicate that particles with thermal energy at room temperature do not bounce off a surface, even when a very weak interaction potential between the particles and the surface is assumed. The loss mechanisms of the center-of-mass energy of nanoparticles colliding with a surface were also investigated. The findings indicate that energy losses to the surface and the rotational degree of freedom are important. The loss to the surface is significant when a harder particle hits a softer surface. This is because the center-of-mass energy is mainly transferred to the surface as elastic energy, and the energy is not effectively transferred back to the particle. Non-spherical silica particles were found to lose more energy than the other types of particles. This phenomenon is due to a large energy transfer to the rotational degree of the freedom upon collision.
Molecular dynamics; Nanoparticle collision; Nanoparticle filtration.