The electrical‐double layer revisited

The electrical-double layer (EDL) model is fundamental to our understanding of interactions in ionic solutions, and widely used chemical, biological, technological contexts, particularly the description aqueous electrolyte solutions. However, recent experiments have raised questions regarding validity this polar, aprotic solvents; some observations, such as a surface potential that changes sign with increasing salt concentration, are not consistent EDL picture. We demonstrate system, acetonitrile at silica interface, solvent organization dictates distributions. Ion-transport measurements nanopores, surface-selective spectroscopy, molecular dynamics simulations reveal distribution ions interface determined by lipid-bilayer-like imposes upon liquid, which accounts for change potential. Our findings emphasize importance including molecules explicitly descriptions solid/liquid interfaces. Key Points In range acetonitrile-based solutions contact silica, effective negative low concentrations positive high concentrations. long-range, preferred locations cations anions. Due organizational effect, classical electrical double-layer modal applicable acetonitrile/silica likely also does hold other systems involving liquids.