Related Experiment Video
Updated: Jul 3, 2026

Generation and Control of Electrohydrodynamic Flows in Aqueous Electrolyte Solutions
Published on: September 7, 2018
Electrostatic relaxation and hydrodynamic interactions for self-diffusion of ions in electrolyte solutions
J-F Dufrêche1, M Jardat, P Turq
1Laboratoire Liquides Ioniques et Interfaces Chargées, Université P. et M. Curie-Paris 6, France. jean-francois.dufreche@upmc.fr
Abstract:
The concentration dependence of self-diffusion of ions in solutions at large concentrations has remained an interesting yet unsolved problem. Here we develop a self-consistent microscopic approach based on the ideas of mode-coupling theory. It allows us to calculate both contributions which influence the friction of a moving ion: the ion atmosphere relaxation and hydrodynamic interactions. The resulting theory provides an excellent agreement with known experimental results over a wide concentration range. Interestingly, the mode-coupling self-consistent calculation of friction reveal a nonlinear coupling between the hydrodynamic interactions and the ion atmosphere relaxation which enhances ion diffusion by reducing friction, particularly at intermediate ion concentrations. This rather striking result has its origin in the similar time scales of the relaxation of the ion atmosphere relaxation and the hydrodynamic term, which are essentially given by the Debye relaxation time. The results are also in agreement with computer simulations, with and without hydrodynamic interactions.
Related Concept Videos
Theory of Strong Electrolytes
Aqueous Solutions and Heats of Hydration
When ionic compounds dissolve in water, the ions in the solid separate and disperse uniformly throughout the solution because water molecules surround and solvate the ions, reducing the strong electrostatic forces between them. This process...
The Debye–Hückel Theory of Electrolyte Solutions
Intermolecular Forces
Ionic Association
The Electrical Double Layer

