Experimental investigation of the Brownian motion dynamics of a polystyrene micro-sphere in liquid water

Abstract

We present experimental observations and investigations of Brownian motion dynamics of polystyrene micro-spheres (diameter 1.053 ± 0.01 μm) immersed in nanopure water . The erratic motion is quantified and described by the diffusion coefficient, D and mean square displacement MSD of the micro-sphere. The Brownian motion of a particle depends on particle size and the nature of its environment. This motion can be used to determine or discriminate fluids. Thus, the accuracy of measurements is significant. In this study, the D and MSD are calculated from micro-sphere trajectories obtained at 26.1 deg-C. Temperature measuring devices, particle detection techniques and correction factors for constrained Brownian motion were implemented to capture the particle's motion dynamics. Measured D values are 0.568 μm²s^-1 and 0.577 μm²s-¹ with 15.96% and 17.66% deviation for 1D and 2D Brownian motion respectively.