Particle-wall alignment interaction and active Brownian diffusion through narrow channels.

Area of Science:

• Physics
• Chemical Engineering
• Materials Science

Background:

• Active particles exhibit self-propulsion, leading to complex transport behaviors.
• Confined geometries, like narrow channels, significantly alter particle dynamics.
• Particle-wall interactions are crucial in dictating transport phenomena in micro/nanoscale systems.

Purpose of the Study:

• To numerically investigate how particle-wall alignment interactions affect active species diffusion.
• To analyze the influence of self-propulsion velocity direction relative to channel walls on diffusion.
• To understand the role of particle properties like chirality in confined diffusion.

Main Methods:

• Numerical simulations were employed to model active particle diffusion.
• The study focused on a structureless, narrow two-dimensional channel.
• Particle-wall interactions were analyzed based on self-propulsion velocity alignment with boundaries.

Main Results:

• Diffusivity is inversely proportional to the square of alignment torque when velocity is perpendicular to walls.
• Diffusion exponentially increases with alignment interaction for acute angles between velocity and walls.
• Alignment interaction's impact depends on particle self-propulsion and chirality.

Conclusions:

• Particle-wall interactions are pivotal in controlling active particle transport in narrow channels.
• The orientation of self-propulsion relative to walls dictates diffusion behavior.
• Findings offer insights into the diffusion of biological and artificial micro/nano-objects in confined environments.