Water flow in carbon nanotubes

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

Sam, Alan (Indian Institute of Technology Madras)
Kannam, Sridhar Kumar (Swinburne University of Technology)
Hartkamp, Remco (TU Delft Process and Energy)
Sathian, Sarith P. (Indian Institute of Technology Madras)

Process and Energy

2017

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.

Carbon nanotubes
Friction
Nanoscale flows
Carbon
Kinematics

http://resolver.tudelft.nl/uuid:937576f9-599e-45d2-82dc-278aee1d590b

https://doi.org/10.1063/1.4985252

2018-06-15

0021-9606

Journal of Chemical Physics, 146 (23)

Institutional Repository

journal article

© 2017 Alan Sam, Sridhar Kumar Kannam, Remco Hartkamp, Sarith P. Sathian