Liquid nucleation around charged particles in the vapor phase

Area of Science:

• Physical Chemistry
• Thermodynamics
• Statistical Mechanics

Background:

• Classical nucleation theory describes phase transitions from a uniform supersaturated vapor.
• Charged particles introduce electrostatic forces that can influence vapor-gas phase behavior.
• Understanding nucleation is crucial for various applications, including atmospheric science and materials processing.

Purpose of the Study:

• To theoretically investigate vapor-to-liquid nucleation induced by a charged spherical particle.
• To analyze the impact of electrostatic fields on phase transitions near the critical point.
• To develop a theoretical framework that accounts for non-uniform fluid phases and self-consistent surface tension.

Main Methods:

• Utilizing a van der Waals free energy model augmented with electrostatic and square-gradient terms.
• Calculating equilibrium density profiles for arbitrary temperatures, particle charges, and vapor densities.
• Numerically describing transition points and providing approximate analytical expressions.

Main Results:

• The charged particle's field gradient destabilizes the vapor phase, initiating nucleation.
• Both nucleating liquid and surrounding vapor phases are spatially non-uniform, deviating from bulk properties.
• Adsorption near the particle changes discontinuously at a first-order phase transition, becoming second-order at higher temperatures.
• A phase diagram illustrates shifts in critical, binodal, and spinodal temperatures due to the field gradient.

Conclusions:

• The presence of a charged particle significantly alters nucleation behavior compared to uncharged systems.
• The electrostatic field gradient expands the operational window of temperature and vapor density for liquid nucleation.
• The developed theory accommodates both sharp and diffuse interfaces, offering a more comprehensive description of nucleation phenomena.