Fractal Structure of Hematite Aggregates
The structure of hematiteaggregates, considered to behave as fractal objects, is studied using static light scattering methods. The fractal dimension obtained from the scattering exponent is found to be dependent on the aggregation mechanism and it ranges from 2.3 for rapid (diffusion limited) to 2.8 for slow (reaction limited) aggregation. Polydispersity and restructuring of aggregates do not affect the relationship between scattering exponent and fractal dimension in these aggregates. Excellent correspondence over a range of temperatures and ionic strengths is obtained between results of experiments using dynamic light scattering to determine aggregation kinetics and those predicted using a modified Smoluchowski model incorporating fractal dimensions.