Accelerating water transport through a charged SWCNT: a molecular dynamics simulation

Area of Science:

• Nanotechnology
• Materials Science
• Physical Chemistry

Background:

• Surface properties like hydrophobicity and charge significantly impact water transport in nanotubes.
• Limited understanding exists regarding the influence of charge density, dipole orientation, and movement on water flow through carbon nanotubes (CNTs).

Purpose of the Study:

• To investigate the transport of single-file water molecules within charged carbon nanotubes.
• To elucidate the molecular mechanisms governing water flow in response to nanotube charge.

Main Methods:

• Molecular dynamics simulations were employed to study water transport in pristine and charged single-wall carbon nanotubes (SWCNTs).
• Analysis focused on water dipole orientation, distribution, flipping behavior, and hydrogen bonding within the nanotube.

Main Results:

• Charged CNTs, both positive and negative, promote water filling via electrostatic interactions.
• Water chains exhibit bipolar properties, with dipoles orienting towards or away from the nanotube center.
• Negatively charged SWCNTs (N-SWCNTs) transition water flow from 'hopping' to 'continuous' mode, reducing energy barriers and enhancing flux.

Conclusions:

• Charged CNTs facilitate enhanced water transport by organizing water molecules and inhibiting chain flipping.
• N-SWCNTs significantly accelerate water transport through strengthened hydrogen bonds and reduced energy barriers.
• Findings offer insights for designing advanced water nanochannels.