Curious Characteristics of Polar and Nonpolar Molecules Confined within Carbon Nanotubes (CNT) of Varied Diameter: Insights from Molecular Dynamics Simulation

Carbon nanotube (CNT) has emerged as a potential candidate for desalination of salty water as well as for purification of various kinds of gaseous and liquid mixtures which is controlled by the interaction of the fluid molecules within the nanocavity of CNT. It is, therefore, worthwhile to investigate the behavior of both the polar and nonpolar fluid molecules within the nanoconfinement of CNT at the molecular level. In the present study, molecular dynamics simulations have been performed to investigate the structure and dynamics of polar and nonpolar molecules within CNTs. Results show the enhancement of confined density with increase in nanotube diameter. Single file flow of water, methanol, and methane inside CNT(6,6) was diminished with increase in nanotube diameter and converted to layered flow for larger CNTs. Surprisingly, results showed controversial effects of nanotube dimension for dynamics of polar and nonpolar fluids, which has been explained in terms of interaction forces acting between fluid...