Ion-ion correlations in concentrated electrolytes using a fluctuating dynamic field theory

Classical models of electrostatic interactions and screening work best when at least one of the objects is dilute. At higher concentrations, correlations due to the long-ranged electrostatic interactions alter the behavior seen. This is relevant for applications such as concentrated electrolyte solutions and in colloidal, polymer, and protein suspensions. In concentrated systems, it is convenient to use a continuum field theory that describes the concentrations of ions instead of explicitly tracking each ion. However, mean field theories cannot easily capture ion-ion correlations and fluctuations. In this talk, we will describe the results of applying a stochastic kinetic theory approach to concentrated charged systems. This method can capture fluctuations and correlations in systems with long-ranged interactions like electrostatic. In particular, we will show how the model produces under-screening in concentrated electrolytes and the role of excluded volume repulsions of the ions due to their finite size.