Particle size and shape and their distribution directly influence a variety of end-use material properties related to packing,
mixing, and transport of powders, solutions, and suspensions. Many of the techniques currently employed for particle size
characterization have found limited applicability for broadly polydisperse and/or nonspherical particles. Here, we introduce
a quadruple-detector hydrodynamic chromatography (HDC) method utilizing static multiangle light scattering (MALS), quasi-elastic
light scattering (QELS), differential viscometry (VISC), and differential refractometry (DRI), and apply the technique to
characterizing a series of solid and hollow polystyrene latexes with diameters in the approximate range of 40–400 nm. Using
HDC/MALS/QELS/VISC/DRI, we were able to determine a multiplicity of size parameters and their polydispersity and to monitor
the size of the particles across the elution profile of each sample. Using self-similarity scaling relationships between the
molar mass and the various particle radii, we were also able to ascertain the shape of the latexes and the shape constancy
as a function of particle size. The particle shape for each latex was confirmed by the dimensionless ratio
ρ ≡
R
G,z
/
R
H,z
which, in addition, provided information on the structure (compactness) of the latexes as a function of particle size. Solid
and hollow polystyrene latex samples were also differentiable using these methods. Extension of this method to nonspherical,
fractal objects should be possible.
Keywords Polymers - Separations/instrumentation - Separations/theory - High performance liquid chromatography