Bottom-Up Construction of the Interaction between Janus Particles.

Area of Science:

• Colloid and Interface Science
• Computational Physics

Background:

• The electrostatic interactions of uniformly charged spheres (colloids) are well-understood.
• Interactions involving nonuniformly charged spheres, such as Janus particles, remain less explored.
• The Derjaguin approximation links sphere-sphere interactions to planar surface interactions.

Purpose of the Study:

• To develop a method for calculating the screened electrostatic interaction between Janus particles.
• To provide an analytical model for Janus particle interactions applicable to coarse-grained simulations.

Main Methods:

• Extended the Derjaguin approximation to derive a quadrature expression for Janus particle interactions.
• Decomposed the interaction into three zones based on azimuthal symmetry.
• Renormalized the effective potential to match exact interactions for favorable orientations.
• Compared analytical results with a rigorous point-wise computational model.

Main Results:

• Developed an analytical expression for the screened electrostatic interaction energy between Janus particles.
• The derived potential accurately predicts interaction energy across various separation distances and orientations.
• The analytical model shows favorable agreement with rigorous computational methods.

Conclusions:

• The new analytical model provides an efficient and generalizable method for simulating Janus particle interactions.
• This approach is suitable for implementation in coarse-grained models without loss of generality.
• Facilitates the study of complex systems involving anisotropic colloidal particles.