Characterization of colloidal hematite particle shape and dispersion behavior

An elliptically polarized light scattering (EPLS) technique for the size and shape characterization of ellipsoidal hematite particles is presented. The hematite particles are synthesized by aging aqueous FeCl(3) or Fe(NO(3))(3) solutions at 100 degrees C. Different reaction conditions create particles of aspect ratios between 1 (spherical) and 8 (elongated). Cross-sectional diameter and aspect ratio are observed as a function of reaction (aging) time. Growth of the elongated particles, as well as their fractal aggregation behavior, is characterized using EPLS and comparisons are made with photon correlation spectroscopy and TEM measurements.