Critical fluctuations in electrolytes with a liquid-liquid phase transition

Near-critical fluctuations of ionic solutions with a liquid-liquid phase transition are investigated by measurements of turbidity and static and dynamic light scattering. Phase diagrams are also presented. The systems are substituted ammonium salts (picrate, nitrate, iodide) dissolved in higher alcohols and water. The correlation lengths, determined from the time correlation functions using the Kawasaki mode coupling theory, also describe the temperature dependence of scattering intensity and turbidity. Depending on the specific properties of the system mean-field or Ising behaviour is observed.