Brownian motion in typical microparticle systems

TL;DR

This paper analyzes two-dimensional Brownian motion of latex beads near a wall, incorporating Faxen's correction to account for wall effects on friction, and calculates mean separation distances using Langevin's model.

Contribution

It provides a detailed analysis of Brownian motion near walls with controlled experiments and applies Faxen's correction to improve the understanding of particle-wall interactions.

Findings

Mean separation distance between particles and wall calculated

Wall proximity modifies friction force on particles

Langevin's model combined with Faxen's correction enhances analysis

Abstract

Many studies on microscopic systems deal with Brownian particles embedded in media whose densities are different from that of the particles, causing them either to sink or float. The proximity to a wall modifies the friction force the particle experiences, being, instead of the Stokes force assumed by Einstein and Langevin, a function of the separation distance, as described by Faxen. In this work we present a thorough analysis of bidimensional Brownian motion using monodisperse suspensions of latex beads with controlled temperatures. By means of Langevin's model and Faxen's correction, we calculate the mean separation distance between the spheres and the bottom of the confining vessel.