RELEVANCE OF REFLECTION IN STATIC AND DYNAMIC LIGHT-SCATTERING EXPERIMENTS

Using a monodisperse PMMA dispersion, it was shown that light reflecti on at the sample cuvette walls may greatly influence the results of bo th static (SLS) and dynamic (DLS) light scattering experiments. Consid ering SLS, this reflection phenomenon mostly causes an overestimation of the scattered intensity at high scattering angles, which may give r ise to the emergence of an additional, artificial peak in the lower re gion of the particle size distribution. On the other hand, the influen ce of reflection on DLS measurements was shown to be particularly impo rtant in the upper region of the particle size distribution. The exper imentally observed phenomena were explained from the basic principles of both particle sizing methods. Finally, it was shown that the distur bing effect of reflection could be avoided by modifying either the har dware or the software of the static and dynamic light scattering techn ique.