Comparison of size distribution data from dynamic light scattering and size-exclusion chromatography

The intensity‐defined distribution functions of hydrodynamic radii of equivalent spheres, Rh, obtained from dynamic light‐scattering experiments using the CONTIN procedure via the Stokes formula were compared with distributions of gyration radii, Rg, determined by size‐exclusion chromatography. The number‐, weight‐, and intensity‐ (z)‐defined Rg distributions accessible from size‐exclusion chromatography experiments were calculated using the Flory‐Fox relation. Reliable ratios of average radii, Rg/Rh, for linear polystyrenes having narrow, broad, or bimodal molecular weight distributions were obtained in toluene. Care should be taken to utilize properly averaged experimental quantities. For instance, the CONTIN DLS data evaluation procedure yields the z‐average of the inverse of the hydrodynamic radius, 〈1/Rh〉z−1. © 1995 John Wiley & Sons, Inc.