Home List of Titles Slip length of water on graphene: limitations of non-equilibrium molecular dynamics simulations
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- Slip length of water on graphene: limitations of non-equilibrium molecular dynamics simulations
- Kannam, Sridhar Kumar; Todd, B. D.; Hansen, J. S.; Daivis, Peter J.
- Data for the flow rate of water in carbon nanopores is widely scattered, both in experiments and simulations. In this work, we aim at precisely quantifying the characteristic large slip length and flow rate of water flowing in a planar graphene nanochannel. First, we quantify the slip length using the intrinsic interfacial friction coefficient between water and graphene, which is found from equilibrium molecular dynamics (EMD) simulations. We then calculate the flow rate and the slip length from the streaming velocity profiles obtained using non-equilibrium molecular dynamics (NEMD) simulations and compare with the predictions from the EMD simulations. The slip length calculated from NEMD simulations is found to be extremely sensitive to the curvature of the velocity profile and it possesses large statistical errors. We therefore pose the question: Can a micrometer range slip length be reliably determined using velocity profiles obtained from NEMD simulations? Our answer is 'not practical, if not impossible' based on the analysis given as the results. In the case of high slip systems such as water in carbon nanochannels, the EMD method results are more reliable, accurate, and computationally more efficient compared to the direct NEMD method for predicting the nanofluidic flow rate and hydrodynamic boundary condition.
- Publication type
- Journal article
- Research centre
- Swinburne University of Technology. Faculty of Engineering and Industrial Sciences
- Research centre
- Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Molecular Simulation
- Journal of Chemical Physics, Vol. 136, no. 2 (Jan 2012), article no. 024705
- Publication year
- FOR Code(s)
- 02 Physical Sciences; 03 Chemical Sciences; 09 Engineering
- Boundary conditions; Carbon nanotubes; Fluids; Hydrodynamics; Liquid; Nanopores
- American Institute of Physics
- Publisher URL
- Copyright © 2012 American Institute of Physics. The published version is reproduced with the kind permission of the publisher.
- Additional information
- The authors acknowledge support from the Victorian Partnership for Advanced Computing HPC Facility and Support Services, an award under the Merit Allocation Scheme on the NCI National Facility at the ANU, and the Lundbeckfonden (Grant No. R49-A5634).
- Full text
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