The polarized interface between quadrupolar insulators: Maxwell stress tensor, surface tension, and potential.

Area of Science:

• Electrostatics
• Dielectric Interfaces
• Macroscopic Electrodynamics

Background:

• Classical Poisson equation neglects quadrupolarization effects at dielectric interfaces.
• Existing models fail to fully describe electrostatic phenomena at polarized interfaces.
• Molecular dynamics simulations suggest diffuse dipole layers at interfaces.

Purpose of the Study:

• To investigate electrostatic phenomena at dielectric interfaces using quadrupolar Maxwell equations.
• To analyze the role of quadrupolarization in surface potential and interfacial properties.
• To develop a macroscopic description of interfacial interactions and their impact on interfacial tension.

Main Methods:

• Application of quadrupolar Maxwell electrostatic equations.
• Analysis of multipole expansion including quadrupole terms.
• Deduction of Maxwell stress tensor in quadrupolar media.
• Modeling of surface dipole moments and polarizability.

Main Results:

• Prediction of surface dipole moments and measurable surface potential jumps at all dielectric interfaces.
• Identification of a diffuse dipole layer near polarized interfaces, consistent with simulations.
• Demonstration of continuous potential and electric field at surfaces with quadrupolar terms.
• Quantification of surface dipole-surface dipole and surface dipole-bulk quadrupole interactions contributing to interfacial tension (tens of mN/m).
• Prediction of dielectrocapillary curves and dielectric susceptibility.
• Determination of the dielectro-Marangoni effect coefficient.

Conclusions:

• Quadrupolar Maxwell equations provide a more accurate description of dielectric interfaces than classical equations.
• Quadrupolarization significantly influences interfacial properties, including interfacial tension and electrical response.
• The developed macroscopic model successfully explains observed phenomena and predicts new effects.