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论文类型：期刊论文

发表时间：2011-06-01

发表刊物：MICROFLUIDICS AND NANOFLUIDICS

收录刊物：SCIE、EI

卷号：10

期号：6

页面范围：1359-1364

ISSN号：1613-4982

关键字：Diffusion mechanism; Diffusion coefficient; Carbon nanotube; Confined water; Molecular dynamics

摘要：The diffusion mechanism and coefficient of water confined in carbon nanotubes (CNTs) of diameter ranging from 8 to 54 are studied by molecular dynamics simulations. It is found that the motions of water molecules inside the CNTs of diameter smaller than 12.2 follow a two-stage diffusion mechanism. Initially, the water diffusion exhibits a long-time super- or sub-diffusion mechanism, and thereafter it transits to the single-file type inside the (6, 6) CNT and shifts to the Fickian type inside the larger CNTs. As for the CNTs of diameter larger than 12.2 , the diffusion of the confined water occurs through the Fickian mechanism, which is identical to that of the bulk water. The simulation results further reveal that the diffusion coefficient of the confined water is non-monotonically dependent on the diameter, which can be ascribed to the double-edged effect of CNTs, i.e., the surface effect and the size effect.