1. Asymmetric dipole distribution of single-file water molecules across nanochannels under high pressure gradient
- Author
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Jian Liu, Qi-Lin Zhang, Rong-Yao Yang, Feng Tao, Han-Wei Yu, and Qi Liu
- Subjects
Nanotube ,Materials science ,02 engineering and technology ,Carbon nanotube ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Molecular physics ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,Dipole ,Molecular dynamics ,Distribution (mathematics) ,Computational chemistry ,law ,0103 physical sciences ,Materials Chemistry ,Molecule ,Nanometre ,Physical and Theoretical Chemistry ,010306 general physics ,0210 nano-technology ,Spectroscopy ,Pressure gradient - Abstract
The dipole distributions of water molecules across the channel of single-walled carbon nanotubes (SWCNTs) under high pressure gradient P are studied using molecular dynamics (MD) simulations. It is found that the profiles of the dipole distributions are highly symmetrical with two peak values around 30° and 150° at zero or low pressure gradient (P ≤ 6MPa), and remarkably asymmetric with the main peak around 30° under high pressure gradient (P ≥ 12MPa). The reason is mainly that molecules can enter into the SWCNTs from two ends under low pressure water, whereas the water molecules can only enter into the tube from one end under high pressure. Further, it also implies that water molecules prefer to retain the hydrogens forward when entering into and passing through the nanotube. Our observations may be instructive for future applications in nanometer scale fluid devices and biological channels.
- Published
- 2018