Gao Wen-Xiu; Wang Hong-Lei; Li Shen-Min
Molecular Dynamics Simulation Study of Structural and Transport Properties of Methanol-Water Mixture in Carbon Nanotubes
ACTA PHYSICO-CHIMICA SINICA, 30:1625-1633, SEP 2014

Molecular dynamics simulations of a methanol-water mixture (molar ratio 1:1) were performed to determine the differences among the structural and transport properties in three carbon nanotube (CNT) systems: an equilibrium system, a system with an external pressure, and a system with a gradient electric field. The simulations showed that in both the equilibrium system and the system with an external pressure, the methanol-water mixture is clearly immiscible in the CNTs, with the water molecules distributed mainly around the tube axis, and the methanol molecules located near the tube wall; however, in the system with a gradient electric field, the hydrophobic CNTs become hydrophilic, and the phenomenon of methanol-water separation disappears. In contrast, unlike the unidirectional transport observed in the system with an external pressure, the particles move in two directions in the system with a gradient electric field, with a flow one order of magnitude larger than that in the corresponding external pressure system. However, in the system with a gradient electric field, the net flux is small, because the flows for the two directions are similar. There is thus a small flux difference between the system with an external pressure and the system with a gradient electric field.

DOI:10.3866/PKU.WHXB201407031

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