Capillary Phase Transitions of Linear and Branched Alkanes in Carbon Nanotubes from Molecular Simulation

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• 作者：Jianwen Jiang ; Stanley I. Sandler
• 刊名：Langmuir
• 出版年：2006
• 出版时间：August 15, 2006
• 年：2006
• 卷：22
• 期：17
• 页码：7391 - 7399
• 全文大小：238K
• 年卷期：v.22,no.17(August 15, 2006)
• ISSN：1520-5827

文摘

Capillary phase transitions of linear (from C₁ to C₁₂) and branched (C₅ isomers) alkanes in single-walled carbonnanotubes have been investigated using the gauge-cell Monte Carlo simulation. The isotherm at a supercritical temperatureincreases monotonically with chemical potential and coincides with that from the traditional grand canonical MonteCarlo simulation, whereas the isotherm at a subcritical temperature exhibits a sigmoid van der Waals loop includingstable, metastable, and unstable regions. Along this loop, the coexisting phases are determined using an Maxwellequal-area construction. A generic confinement effect is found that reduces the saturation chemical potential, lowersthe critical temperature, increases the critical density, and shrinks the phase envelope. The effect is greater in a smallerdiameter nanotube and is greater in a nanotube than in a nanoslit.