SCALING DESCRIPTION OF THE STRUCTURE FACTOR OF FRACTAL SOOT COMPOSITES

This paper studies the static structure factor of a system of fractal aggregates at various degrees of densification. The system we use for this study is carbonaceous soot, which is composed of diffusion limite d cluster aggregates with a fractal dimension of 1.8. The range of den sity is great, from the aerosol to a system of lightly touching cluste rs and then to ground and compressed samples. The data involve a combi nation of light scattering and small-angle x-ray scattering over a q r ange of 3 x 10(-3 less than or equal to)q less than or equal to 6 nm(- 1). We are able to explain all the features of the data with scaling a rguments based on comparisons of the scattering length scale q(-1), wh ere q is the magnitude of the scattering wave vector, and the various length scales of the system that are density dependent. [S1063-651X(98 )00410-3].