Flow of Polar and Nonpolar Liquids through Nanotubes: A Computational Study

We perform ab initio density functional calculations to study the flow of water, methanol and dimethyl ether through nanotubes of carbon and boron nitride with different diameters and chiralities. The liquids we choose are important solvents, with water and methanol being polar and dimethyl ether being non-polar. In terms of activation barriers for liquid transport, we find the molecular-level drag to decrease with decreasing nanotube diameter, but to be rather independent of the chiral index. We also find molecules with higher polarity to experience higher drag during the flow. Counter-intuitively, we find the drag for water in boron nitride nanotubes not to exceed that in carbon nanotubes due to frustration in competing long-range Coulomb interactions.