REFLECTION PHENOMENA IN PARTICLE SIZING BY STATIC AND DYNAMIC LIGHT-SCATTERING

Using a monodisperse poly(methyl methacrylate) dispersion it was shown that light reflection at the sample cuvette walls may greatly influen ce the results of both static (SLS) and dynamic (DLS) light scattering experiments. Considering SLS, this reflection phenomenon mostly cause s an overestimation of the scattered intensity at high scattering angl es, which may give rise to the emergence of an additional, artificial peak in the lower region of the particle size distribution. On the oth er hand, the influence of reflection on DLS experiments was shown to b e particularly important in the upper region of the particle size dist ribution. The experimentally observed phenomena were explained from ba sic principles of both particle sizing methods. Finally, it was shown that the disturbing effect of reflection could be avoided by modifying either the hardware or the software of the SLS and DLS techniques.