PARTICLE-SIZE ANALYSIS BY DYNAMIC LIGHT-SCATTERING

Dynamic light scattering is an established technique for measuring the average size and size distribution of particles in a suspension. The technique has the advantage of being fast and non-invasive, but it does require low particle concentrations. As well, dynamic light scattering results are often open to misinterpretation if one is unaware of the state of the sample and the method of data analysis. The following discussion reviews some of the basic concepts of dynamic light scattering and outlines some of the pitfalls that are often encountered in data interpretation. A modification of dynamic light scattering, diffusing wave spectroscopy, can be used to obtain approximate size information at higher particle concentrations. The fundamentals of this new technique are summarized.