The effects of sodium dodecyl sulfate (SDS) concentration (≤ 10 mass %), temperature (35 and 50 °C), and pressure (0.1 to 100 MPa) on the cooperative diffusion coefficient and static correlation length of micelles in solutions in 1 M NaCl were studied using static and dynamic light scattering. These data are interpreted in terms of models of dilute and semidilute solutions of rod-like polymers. The results indicate that the effects of pressure are most significant near the crossover concentration between dilute and semidilute solution behavior. This concentration is a function of temperature and pressure because both of these thermodynamic parameters affect the mean micellar size.

Light scattering in the backscattering geometry, and transmission measurements are used to size monodisperse spherical particles in solutions. The concentration of spheres spans the scattering to range from single scattering to very highly multiple scattering. These experiments were performed by varying volume fractions of polystyrene latex spheres of nominal diameter 0.136 and 1.015 m. Transmission measurements were performed as a function of particle size, volume fraction, and sample thickness with a spectrophotometer equipped with an integrating sphere. The data show that for thin samples the percent transmission is nearly independent of particle size and depends only on L/l*, the ratio of the sample thickness L to the transport mean free path l*. By fitting the autocorrelation functions of samples obtained from known sphere sizes to a generalized cumulants model, which describes both the highly multiple scattering regime and the singly scattering regime, parameters were found that allow particle sizes to be determined over a wide range of scattering strengths. For samples of unknown size, this method can size monodisperse spherical particles in highly scattering solutions to better than 10%.

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