Light scattering from coloured systems: An example of polyaniline dispersions

Static light scattering of highly diluted dispersions in 0.005 M H2SO4 was used to determine particle parameters of polyaniline dispersions stabilized with colloidal silica. The refractive index of poryaniline n = 1.8 and the refractive index increment (dn/dc) = 0.22 cm(3) g(-1) at lambda = 532 nm w ere determined. The light scattering data are affected by the absorption of the green polyaniline and by a small amount of aggregates. The absorption has a negligible effect on the results. The influence of the aggregates was corrected by using the intensity-weighed size distributions determined by dynamic light scattering at different angles and by the two-component separ ation in static light scattering. Both procedures yield the same result.