Data from "Breakdown of Nernst-Einstein Relation in Carbon Nanotube Porins"

Full dataset from the manuscript, including data from all main text, extended data, and supplementary materials sections. <br> Abstract: For over 100 years, the Nernst-Einstein relation has provided a universal link between a charged particle electrophoretic mobility and its diffusion coefficient. Here, we report experimental measurements of diffusive and electrophoretically-driven K⁺ ion transport in narrow pores of 0.8 nm diameter single-wall carbon nanotubes (CNTs), which indicate that the Nernst-Einstein relation breaks down by over three orders of magnitude in these channels. To explain these findings, we carried out all-atomistic molecular dynamics simulations using polarizable force fields that showed that the K⁺ ion diffusion in the narrow pore of the CNT in the presence of a single file water chain was at least three orders of magnitude slower than the K⁺ ion diffusion in bulk solution. Intriguingly, the simulations also revealed a novel mechanism for electrophoretic transport of K⁺ ions where the single file water chain disintegrated in the presence of applied electric fields, forming distinct ion-water clusters, which then traversed the CNT at significantly higher velocities. Finally, we demonstrate that although the individual ion-water clusters still obey the Nernst-Einstein relation, the overall relation breaks down because of two distinct ion transport mechanisms for concentration gradient-driven versus electric field-driven ion flows in these channels.