Self-Diffusiophoresis of Slender Catalytic Colloids.

Area of Science:

• Fluid dynamics
• Chemical physics
• Soft matter physics

Background:

• Self-diffusiophoresis drives particle motion via solute gradients.
• Continuum models describe particle-solute interactions with first-order kinetics.
• Slender-body theory simplifies analysis for elongated particles.

Purpose of the Study:

• To develop algebraically accurate approximations for self-diffusiophoresis of axisymmetric particles.
• To analyze the asymptotic limit of slender particles (ϵ ≪ 1).
• To improve upon conventional asymptotic expansions in inverse powers of ln(ϵ).

Main Methods:

• Utilizing a continuum description with diffusio-osmotic slip at the particle boundary.
• Employing slender-body theory for the asymptotic limit ϵ ≪ 1.
• Solving coupled linear integral equations for solute-sink and Stokeslet distributions.
• Applying finite-difference schemes for numerical solutions and large-Damköhler number analysis.

Main Results:

• Algebraically accurate approximations for particle speed were derived.
• The method yields more useful approximations than conventional inverse ln(ϵ) expansions.
• Numerical solutions for spheroidal particles show excellent agreement with analytical approximations.
• A large-Damköhler number analysis revealed subtle nonuniformities requiring careful treatment.

Conclusions:

• The developed slender-body theory provides accurate predictions for self-diffusiophoresis.
• This approach offers a significant improvement for analyzing slender particle dynamics.
• The findings are relevant for understanding micro- and nanomotor behavior.