Temperature and size effects on diffusion in carbon nanotubes

被引:42
作者
Jakobtorweihen, S.
Keil, F. J.
Smit, B.
机构
[1] Hamburg Univ Technol, D-21073 Hamburg, Germany
[2] Univ Amsterdam, HIMS, NL-1018 WV Amsterdam, Netherlands
[3] Ecole Normale Super Lyon, CECAM, F-69364 Lyon 7, France
关键词
TRANSPORT; DEPENDENCE; SORBATES;
D O I
10.1021/jp063424+
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
We study the self-diffusion of simple gases inside single-walled carbon nanotubes at the zero-loading limit by molecular dynamics simulations. The host-framework flexibility influence is taken into account. In particular, we study the influences of nanotube size and temperature. For the carbon-nanotube radius-dependent self-diffusivities, a maximum is observed, which resembles the so-called levitation effect. This occurs for pores having a radius comparable to the position of the interaction-energy minimum. Surprisingly, the temperature influence is not uniform throughout different pore sizes. Diffusivities are expected to increase with temperature. This effect is observed for carbon nanotubes distinctly larger than the guest molecules. Remarkably, for smaller pores, the self-diffusivities decrease with increasing temperature or exhibit a maximum in the temperature dependence. This effect is caused by competing influences of collision frequency and temperature.
引用
收藏
页码:16332 / 16336
页数:5
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