IMPROVED PARTICLE-SIZE DISTRIBUTION MEASUREMENTS USING MULTIANGLE DYNAMIC LIGHT-SCATTERING .2. REFINEMENTS AND APPLICATIONS

Dynamic light scattering (DLS) is widely used for particle size determ ination in the sub-micrometer range. The utility of combining simultan eous multiangle DLS and static light scattering (SLS) in obtaining mor e robust and reproducible particle size distributions has recently bee n demonstrated (Langmuir 1995, 11, 2480-2485). This approach yields ex cellent results but is tedious and demands high-quality SLS data which , in turn, require a sophisticated and high-quality photometer system. In this paper we investigate ways to improve further the attractivene ss of this approach by examining two possible schemes to reduce the ex perimental overhead in these measurements. We consider combining SLS m easurements with only a few angles of DLS data and also recording only DLS data at many angles and iteratively reconstructing the SLS data d uring the data analysis. We show that in the latter case it is possibl e to obtain particle size distribution results as good as those obtain ed with simultaneous multiangle DLS and SLS, by doing DLS at 10 scatte ring angles and perhaps as few as 5 angles. This approach has a number of advantages including shorter measurement times and the ability to use lower quality photometer systems which may not be capable of preci sion SLS measurements.