We theoretically investigate the nucleation of liquid droplets from vapor in the presence of a charged spherical particle. Due to field gradients, sufficiently close to the critical point of the vapor–gas system, the charge destabilizes the vapor phase and initiates a phase transition. The fluid’s free energy is described by the van der Waals expression augmented by electrostatic energy and a square-gradient term. We calculate the equilibrium density profile at arbitrary temperatures, particle charges, and vapor densities. In contrast to classical nucleation theory, here, both liquid and vapor phases are different from the bulk phases because they are spatially nonuniform. In addition, the theory applies to both sharp and diffuse interfaces and calculates the surface tension self-consistently. We find the composition profiles and integrate them to get the adsorption near the particle. We find that the adsorption changes discontinuously at a first-order phase transition line. This line becomes a second-order phase transition at high enough temperatures. We describe the transition point numerically and provide approximate analytical expressions for it. Similarly to prewetting, the adsorption diverges at the binodal phase boundary. We construct a phase diagram indicating changes in the binodal, spinodal, and critical temperature. It is shown that the field gradient enlarges the range of temperature and vapor density where liquid can nucleate.

Antagonistic ions have opposite preferential solvation in two liquids. Their uneven distribution across the liquid–liquid interface creates an asymmetric electric double layer. In this work we calculate the resulting contribution to the surface tension.

We look at the influence of external fields on systems described by generic free energy functional of the order parameter. The external force may have arbitrary spatial dependence, and the order parameter coupling may be nonlinear. The treatment generalizes seemingly disparate works, such as pure fluids, liquid and polymer mixtures, lipid monolayers, and colloidal suspensions in electric fields, fluids and nematics in gravity, solutions in an ultracentrifuge, and liquid mixtures in laser radiation. The phase lines and thermodynamic behavior are calculated on the mean-field level. We find a ``surface' critical point that can be shifted to higher or lower temperatures than the bulk critical point. Below this point, the transition from a ``gas' phase to a ``liquid' phase is first-order, while above it, the transition is second-order. The second-order line is affected by the spatial dependence of the force, while the first-order line is universal.Moreover, the susceptibility may diverge at a finite location ${\bf r}$. Several analytical expressions are given in the limit where a Landau expansion of the free energy is valid.

We look at the influence of external fields on systems described by generic free energy functional of the order parameter. The external force may have arbitrary spatial dependence and the coupling to the order parameter may be nonlinear. The treatment generalizes seemingly disparate works, such as pure fluids, liquid and polymer mixtures, lipid monolayers, and colloidal suspensions in electric fields, fluids and nematics in gravity, solutions in an ultracentrifuge, and liquid mixtures in laser radiation. The phase lines and thermodynamic behavior are calculated on the mean-field level. We find a "surface" critical point that can be shifted to higher or lower temperatures compared to the bulk critical point. Below this point, the transition from a "gas" phase to a "liquid" phase is first-order, while above it the transition is second-order. Moreover, the susceptibility may diverge at a finite location r. Several analytical expressions are given in the limit where a Landau expansion of the free energy is valid.

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