title: Ion-specific anomalous electrokinetic effects in hydrophobic nanochannels.
abstract: We show with computer simulations that anomalous electrokinetic effects, such as ion specificity and nonzero zeta potentials for uncharged surfaces, are generic features of electro-osmotic flow in hydrophobic channels. This behavior is due to the stronger attraction of larger ions to the "vapor-liquidlike" interface induced by a hydrophobic surface. We propose an analytical model involving a modified Poisson-Boltzmann description for the ion density distributions that quantitatively predicts the anomalous flow profiles. This description includes as a crucial component an ion-size-dependent hydrophobic solvation energy. These results provide an effective framework for predicting ion-specific effects, with potentially important implications for biological modeling.
authors.affiliation: Université de Lyon, Université Lyon 1, LPMCN, and CNRS, UMR 5586, F-69622 Villeurbanne Cedex, France.
authors.forename: David M
authors.initials: DM
authors.lastname: Huang
authors.forename: Cécile
authors.initials: C
authors.lastname: Cottin-Bizonne
authors.forename: Christophe
authors.initials: C
authors.lastname: Ybert
authors.forename: Lydéric
authors.initials: L
authors.lastname: Bocquet
mesh_terms: D003198:Computer Simulation; D004553:Electric Conductivity; D057927:Hydrophobic and Hydrophilic Interactions; D007477:Ions / Q000737:chemistry*; D008954:Models, Biological; D049329:Nanostructures / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D012974:Sodium Iodide / Q000737:chemistry
chemical_list: D007477:Ions; D012965:Sodium Chloride; D012974:Sodium Iodide