DETERMINATION OF LIGHT-SCATTERING FORM-FACTORS OF LATEX PARTICLE DIMERS WITH SIMULTANEOUS STATIC AND DYNAMIC LIGHT-SCATTERING IN AN AGGREGATING SUSPENSION

Light-scattering form factors and hydrodynamic radii of latex particle dimers were obtained by time-resolved experiments in aggregating susp ensions of latex particles with radii of 155 and 290 nm. The method re lies on a simultaneous measurement of static and dynamic light scatter ing at different angles with a fiberoptics-based multiangle instrument in the early stages of the aggregation, where only particle dimers ar e formed. Combined analysis of such simultaneous experiments allows th e determination of absolute coagulation rate constants without referen ce to light-scattering and hydrodynamic properties of the dimers. The knowledge of this rate constant permits the evaluation of the dimer fo rm factors from the static or the dynamic experiment. The experimental ly determined form factors agree well with results of calculation base d on modal analysis and discrete dipole approximation.