AVS 49th International Symposium
    Nanometer Structures Tuesday Sessions
       Session NS-TuP

Paper NS-TuP3
Molecular Dynamics Simulations of Nanofluidics

Tuesday, November 5, 2002, 5:30 pm, Room Exhibit Hall B2

Session: Nanometer Structures A
Presenter: K. Lee, University of Florida
Authors: K. Lee, University of Florida
S.B. Sinnott, University of Florida
Correspondent: Click to Email
The design of ultrafiltration membranes using carbon nanotubes to allow gases to selectively pass through the membrane depends on the understanding of the diffusion and adsorption of the gases within the carbon nanotubes. The nanofluidics of hydrocarbons, oxygen, and carbon dioxide has been studied with molecular dynamics simulations in our research. These macroscopic behaviors can be simulated with multiple integrations of the interactions among the atoms in a system. The interatomic forces in the simulations are calculated using a classical reactive empirical bond-order hydrocarbon potential coupled to Lennard-Jones and Coulombic potentials. For a shorter time period, the location, the trace, and the orientation of the gas molecules in the nanotubes are affected by the diameters of the nanotubes, and the structures of the carbon nanotubes. The transport of gas molecules for a longer time period is described by nonequilibrium followed by equilibrium states. Until reaching the equilibrium state, the gas density in a carbon nanotubes increases on and levels off. During the nonequilibrium state, the gas molecules move back and forth through the nanotube. This behavior and the time for the level-off are affected by the concentration of gas molecules both in and outside of the carbon nanotube. It is found that the molecular volumes of the gas molecules and the composition of the gas mixtures also have an important effect on the separation behavior.