A new method for determining the size distribution of particles in colloidal suspensions
Don Grant – CT Associates, Inc., Eden Prairie, MN
The size distribution of particles in colloidal suspensions is often measured using either dynamic light scattering or laser diffraction. These ensemble techniques observe the properties of multiple particles simultaneously and can only measure relative concentrations. The technique described in this presentation measures individual particles and allows determination of particle number concentrations in multiple size bins ranging from 15 nm to 500 nm. The technique involves forming an aerosol such that the particles in the colloidal suspension are individually dispersed in air. The size distribution is then measured using a Scanning Mobility Particle Sizer (SMPS).
Measurements made in several colloidal suspensions will be presented and compared to measurements made using dynamic light scattering. Use of the method to track changes in particle size distribution during handling of a colloidal suspension will also be presented.
CTA publication #77: Presented at the Particle Society of Minnesota annual meeting, March 19, 2008