Water flow in carbon nanotubes: The effect of tube flexibility and thermostat

Alan Sam, Sridhar Kumar Kannam, Remco Hartkamp, Sarith P. Sathian

Research output: Contribution to journalArticleScientificpeer-review

32 Citations (Scopus)
21 Downloads (Pure)

Abstract

Although the importance of temperature control in nonequilibrium molecular dynamics simulations is widely accepted, the consequences of the thermostatting approach in the case of strongly confined fluids are underappreciated. We show the strong influence of the thermostatting method on the water transport in carbon nanotubes (CNTs) by considering simulations in which the system temperature is controlled via the walls or via the fluid. Streaming velocities and mass flow rates are found to depend on the tube flexibility and on the thermostatting algorithm, with flow rates up to 20% larger when the walls are flexible. The larger flow rates in flexible CNTs are explained by a lower friction coefficient between water and the wall. Despite the lower friction, a larger solid-fluid interaction energy is found for flexible CNTs than for rigid ones. Furthermore, a comparison of thermostat schemes has shown that the Berendsen and Nosé-Hoover thermostats result in very similar transport rates, while lower flow rates are found under the influence of the Langevin thermostat. These findings illustrate the significant influence of the thermostatting methods on the simulated confined fluid transport.

Original languageEnglish
Article number234701
Number of pages7
JournalJournal of Chemical Physics
Volume146
Issue number23
DOIs
Publication statusPublished - 2017

Keywords

  • Carbon nanotubes
  • Friction
  • Nanoscale flows
  • Carbon
  • Kinematics

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