Strong and Weak Interactions of Colloidal Particles with High Surface Potentials

Area of Science:

• Physical Chemistry
• Surface Science
• Electrostatics

Background:

• Understanding electrostatic interactions between surfaces is critical in various scientific and engineering fields.
• High surface potentials significantly influence inter-surface forces, necessitating accurate calculation methods.

Purpose of the Study:

• To develop a straightforward method for calculating interaction forces and energy per unit area between dissimilar plates at high potentials.
• To derive expressions for interaction free energy between dissimilar spheres with high surface potentials using established methods.

Main Methods:

• Application of Derjaguin's method and the improved Derjaguin' method.
• Derivation of formulae for interaction free energy applicable to both dissimilar plates and spheres.
• Categorization of interaction formulae into strong and weak interaction groups.

Main Results:

• A simple method for calculating interaction force and energy per unit area for dissimilar plates was presented.
• Expressions for interaction free energy between dissimilar spheres with high surface potentials were derived.
• The transition point between strong and weak interactions was identified at kappa h=4 for plates and kappa h=2.8 for spheres, with a maximum relative error of approximately 10%.

Conclusions:

• The developed method provides a simplified approach to quantifying electrostatic interactions between dissimilar surfaces.
• The derived formulae offer distinct calculations for strong and weak interaction regimes.
• The findings are relevant for applications involving charged surfaces in close proximity.