Related Experiment Video
Updated: Jun 20, 2026

Spatial Separation of Molecular Conformers and Clusters
Published on: January 9, 2014
Ion distribution around a charged rod in one and two component solvents: preferential solvation and first order
1Department of Physics, Kyoto University, Kyoto 606-8502, Japan. okamoto_r@scphys.kyoto-u.ac.jp
Abstract:
In one and two component polar solvents, we calculate the counterion distribution around an ionizable rod treating the degree of ionization alpha as an annealed variable dependent on its local environment. In the two component case, we take into account the preferential solvation of the charged particles and the short-range interaction between the rod and the solvent. It follows a composition-dependent mass action law. The composition becomes heterogeneous around a charged rod on a mesoscopic scale, strongly affecting the counterion distribution. We predict a first order phase transition of weak-to-strong ionization for hydrophobic chains. This transition line starts from a point on the solvent coexistence curve and ends at an ionization critical point. The composition heterogeneity is long-ranged near the solvent critical point.
Related Concept Videos
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...
Ionic Association
Intermolecular Forces
Intermolecular Forces in Solutions
When the strengths of the intermolecular forces of attraction between solute and solvent species in a solution are no different than those present in the separated components, the solution is formed with no accompanying energy change. Such a solution is called an ideal solution. A mixture of ideal gases (or gases such as helium and argon,...
The Colloidal State
Ion Exchange

