Self-diffusiophoretic propulsion in wedge confinement: The role of phoretic interactions

Area of Science:

• Physics
• Physical Chemistry
• Fluid Dynamics

Background:

• Self-diffusiophoresis describes particle motion driven by self-generated chemical gradients.
• Confined geometries, such as wedges, can significantly alter microparticle dynamics.
• Understanding particle behavior in confined spaces is crucial for microfluidic applications.

Purpose of the Study:

• To investigate the self-diffusiophoretic motion of a spherical particle within a wedge-shaped domain.
• To derive analytical expressions for the particle's phoretic velocity in this geometry.
• To analyze the influence of wedge angle and particle position on motion.

Main Methods:

• Solving the Laplace equation for the concentration field using the Fourier-Kontorovich-Lebedev transform.
• Employing the method of images to account for boundary conditions and surface activity.
• Deriving far-field expressions for the self-induced phoretic velocity.

Main Results:

• The wedge geometry significantly impacts both the magnitude and direction of the particle's self-diffusiophoretic velocity.
• Concentration disturbances near wedge corners contribute to the phoretic velocity.
• Phoretic interactions, not hydrodynamic effects, were the focus.

Conclusions:

• The study presents a systematic framework for calculating phoretic velocities in confined geometries.
• Findings have implications for designing and controlling autophoretic particles in microfluidics.
• Wedge geometry fundamentally influences particle self-propulsion mechanisms.