Quartz/Aqueous Electrolyte Solution Interface: Molecular Dynamic Simulation and Interfacial Potential Measurements

Abstract

In this complementary experimental and theoretical study, we employ surface and electrokinetic potential measurements and equilibrium molecular dynamics (MD) techniques to study the electrical interfacial layer between aqueous solutions of electrolytes and an oxide solid surface. More specifically, we investigate the behavior of a prototypical model system consisting of the (0001) quartz surface in contact with aqueous solutions of alkali metal salts under different conditions. The inner surface potential and electrokinetic ζ-potential were measured by means of single crystal electrodes and via streaming current measurements, respectively. Calculated ζ-potentials allowed us to benchmark MD simulations against experiments, thereby, on the one hand, verifying the validity of our strategy and, on the other hand, enabling a detailed molecular picture of the investigated phenomena and elucidating the role of both water and ions in the formation of the multilayered quartz/aqueous electrolyte interface.