Nucleation around a charged particle in a polar environment

Condensation of drops from a vapor phase is crucial to understanding many research fields, particularly environmental science. Droplets are formed by nucleation, where the vapor is supersaturated, but the creation of a new phase is delayed by an energy barrier. In recent years, ion-induced nucleation has been studied extensively. The Thomson model showed that nucleation around a charged particle in a nonpolar environment reduces the energy barrier due to electrostatic interactions.

We developed a mean-field model for nucleation around a charged particle, such as an aerosol or dust particle, surrounded by vapor of a polar fluids. In the first part of the work, we generalized the Thomson model to polar fluids, by assuming a well-defined liquid-vapor interface and existence of dissociated ions. By solving the Poisson-Boltzmann equation, we obtained the electrostatic potential and energy barrier for nucleation. The model reduces to the Thomson model where the Debye screening length is very large, and to electro-wetting when the Debye's length is very small.

In the second part, we looked at nucleation outside of the binodal, for undersaturated vapor. We minimized the Gibbs energy to find the fluid density profiles as a function of distance from the particle, depending on the undersaturation, temperature and salt concentration. The phase diagram showing where this special charge-induced nucleation occurs is calculated.