Aggregation in the β-FeOOH-Potassium Oleate System

Abstract The aggregation of β-FeOOH particles after adsorption of potassium oleate was studied by means of the Electric Light Scattering method. The aggregates obtained on both sides of the isoelectric point have different electrooptical behavior at low frequencies of applied electric field as a consequence of various orientations due to the "permanent" dipole moments or slow electric polarizability. The time dependence of aggregate length growth was investigated and power law behavior was observed. The obtained power coefficient is independent of the type of measured average length which could be related to the self similarity of aggregates. From a kinetic study of the growth of aggregates a fractal dimension of about 1.8 was calculated, which is in good agreement with computer simulation models and experimental results.