Phoresis kernel theory for passive and active spheres with nonuniform phoretic mobility.

Area of Science:

• Physics
• Soft Matter Physics
• Chemical Engineering

Background:

• Phoretic phenomena govern microparticle motion driven by gradients.
• Understanding particle dynamics requires linking velocities to field distributions.

Purpose of the Study:

• Establish a direct connection between phoretic sphere velocities and driving fields/fluxes.
• Introduce geometry-based phoresis kernels to quantify local contributions to particle dynamics.

Main Methods:

• Development of geometry-based phoresis kernels.
• Analysis of translational and rotational velocities based on field distributions.
• Case studies including self-phoretic axisymmetric and non-axisymmetric particles.

Main Results:

• Kernels quantify local field/flux contributions to particle dynamics.
• Field kernels for passive and active particles share functional forms.
• Uniform phoretic mobility leads to translational motion but no rotation.

Conclusions:

• The introduced kernels provide a unified framework for analyzing phoretic particle motion.
• Insights into rotational dynamics are crucial for understanding complex active matter systems.
• The study offers a new perspective on the interplay between particle geometry, surface properties, and external fields.