Light Scattering Spectroscopy as a Tool for Studying Macromolecular Dynamics and Chemical Kinetics

Abstract

Light scattering has been used for about the past 25 years to determine such static properties of polymers in solution as molecular weights, solution virial coefficients, molecular shapes and characteristic dimensions, molecular optical anistropies and molecular weight and size distributions of polydisperse samples.1 In all of these cases the measured quantity is the frequency integrated intensity of scattered light as a function of scattering angle. In experiments of this type, no attempt is made to measure the spectral distribution of the scattered light. Since the width of the scattered spectral distribution is usually very small, the tools to perform this additional analysis were not available. Recently, however, with the development of lasers and associated techniques such measurements have become commonplace. This new field, light scattering spectroscopy, extends the light scattering technique to the measurement of dynamic quantities, such as translational and rotational diffusion coefficients, intramolecular relaxation times and chemical reaction rate constants.