Anisotropic colloidal interactions & assembly in AC electric fields

Area of Science:

• Colloid science
• Computational physics
• Materials science

Background:

• Anisotropic colloidal particles exhibit complex behaviors in electric fields.
• Accurate modeling requires understanding dipole-field and dipole-dipole interactions.
• Existing models may not capture behavior across all concentrations and field strengths.

Purpose of the Study:

• To develop and validate analytical potentials for simulating anisotropic colloidal particles in AC electric fields.
• To introduce an inverse Monte Carlo simulation algorithm for optimizing these potentials.
• To identify a potential model suitable for diverse microstructures and ordering.

Main Methods:

• Analytical potential identification for dipole-field and dipole-dipole interactions.
• Inverse Monte Carlo simulation to match experimental and simulated particle distribution functions.
• Testing potentials across varying electric field amplitudes, concentrations, and particle ordering.

Main Results:

• Two analytical potentials were identified that accurately capture experimental observations.
• An effective ellipsoidal point dipole potential is suitable for low concentrations.
• A novel stretched point dipole potential accurately models particle behavior at all concentrations and field strengths.

Conclusions:

• The stretched point dipole potential offers a simple, accurate, and adjustable model for field-mediated microstructures.
• This potential can be applied to predict and control the assembly of anisotropic particles.
• The findings advance the understanding of electric field-driven self-assembly in colloidal systems.