Dynamic Light Scattering (DLS)

Abstract

Particles dispersed in a solution are constantly moving in Brownian motion. Since this Brownian motion depends on the velocity of the particle size, the size can be estimated by observing the fluctuation corresponding to this velocity. By obtaining the autocorrelation function of the observed fluctuation, the particle size and distribution can be obtained. Dynamic light scattering (DLS) uses the above principle and provides size information of a wide range of particles easily and accurately. Since the size information of particles, molecular aggregates, and emulsion droplet is extremely important, DLS is widely preferred by many colloid researchers. However, data analysis of DLS is based on the assumption that the particles are uniform and spherical. It should also be noted that the obtained size includes a solvated layer around the particles. Due to its nature, other equipment must be used to obtain detailed information such as the shape. The principle and detailed analysis method by DLS measurement will be described in this section.