Electroprewetting near a flat charged surface.

Area of Science:

• Physical Chemistry
• Surface Science
• Fluid Dynamics

Background:

• Understanding fluid behavior at interfaces is crucial for various physical and chemical processes.
• Ionic fluids near charged surfaces experience complex electrostatic interactions.
• The interplay of van der Waals forces, ions, and charged surfaces dictates wetting phenomena.

Purpose of the Study:

• To investigate the wetting behavior of a classical van der Waals fluid with dissociated ions on a charged flat surface.
• To analyze the effects of dielectrophoretic and electrophoretic forces on fluid density profiles.
• To determine the critical surface potential for prewetting and map the phase diagram.

Main Methods:

• Analytical and numerical calculations of fluid density profiles.
• Determination of energy integrals.
• Phase diagram analysis, including first-order and second-order transition lines.

Main Results:

• Dielectrophoretic and electrophoretic forces increase fluid density near the charged wall.
• The critical surface potential for prewetting was successfully obtained.
• A critical point was identified in the phase diagram where first-order and second-order transitions meet, with variable critical temperature relative to bulk.

Conclusions:

• Charged surfaces and ions significantly modify fluid wetting properties.
• The findings provide insights into droplet nucleation around charged atmospheric particles.
• The study may explain deviations observed in atmospheric nucleation rate experiments.