Molecular dynamics investigations of ionic conductance at the nanoscale: Role of the water model and geometric parameters

Abstract

Ultra-efficient transport of water and ions at the nanoscale is studied through molecular dynamics simulations. Carbon nanotubes (CNTs) are used here as nanofluidic devices owing to their smooth inner structure and the compromise of a very simple composition for a tremendous variety of properties. Transport of solvated ions moving inside the carbon nanotube under the application of an external potential difference allowed the measurement of the ionic current established through the internal area of the tube. To be as exhaustive as possible, three popular water models were tested to investigate ionic transport inside this artificial nanochannel. The key geometric parameters of the carbon structure were also varied, revealing a peculiar dependence of the ionic conductance on each studied parameter in accordance with the theoretical model presented in this paper.