Ionic transport through sub-10 nm diameter hydrophobic high-aspect ratio nanopores: experiment, theory and simulation Auteur(s): Balme Sébastien, Picaud Fabien, Manghi Manoel, Palmeri J., Bechelany Mikhael, Cabello-Aguilar Simon, Abou Chaaya Adib, Miele Philippe, Balanzat Emmanuel, Janot Jean-Marc (Article) Publié: Scientific Reports, vol. 5 p.10135 (2015) Texte intégral en Openaccess : Ref HAL: hal-01162029_v1 DOI: 10.1038/srep10135 WoS: 000355647800001 Exporter : BibTex | endNote 45 Citations Résumé: Fundamental understanding of ionic transport at the nanoscale is essential for developing biosensors based on nanopore technology and new generation high-performance nanofiltration membranes for separation and purification applications. We study here ionic transport through single putatively neutral hydrophobic nanopores with high aspect ratio (of length L = 6 μm with diameters ranging from 1 to 10 nm) and with a well controlled cylindrical geometry. We develop a detailed hybrid mesoscopic theoretical approach for the electrolyte conductivity inside nanopores, which considers explicitly ion advection by electro-osmotic flow and possible flow slip at the pore surface. By fitting the experimental conductance data we show that for nanopore diameters greater than 4 nm a constant weak surface charge density of about 10−2 C m−2 needs to be incorporated in the model to account for conductance plateaus of a few pico-siemens at low salt concentrations. For tighter nanopores, our analysis leads to a higher surface charge density, which can be attributed to a modification of ion solvation structure close to the pore surface, as observed in the molecular dynamics simulations we performed. |