چکیده :
It is well known that clusters generated from colloidal aggregation driven by Brownian motion are typical fractal
objects with the fractal dimension in the range of 1.75–1.85 under the diffusion-limited cluster aggregation
(DLCA) conditions. In thiswork, we review and analyze the values of the fractal dimension for DLCA clusters experimentally
determined in the literature. It is found that the value of the fractal dimension decreases significantly
as the primary particle radius increases. Then, we have properly designed the DLCA experiments, using
different radii of the primary particles, and determined the fractal dimensions of the generated clusters. Our results
havewell confirmed that the fractal dimension indeed decreases as the particle radius increases. To explore
themechanismleading to such dependence, we have performed intense computations through the full T-Matrix
theory, and we conclude that this is not related to the effect of the intra-clustermultiple scattering on the slope of
the scattering structure factor. The large fractal dimensions of the clusters generated by very small nanoparticles
could be explained by thermal restructuring due to their low bonding energies, but no clear explanation can be
given for the small fractal dimensions of the clusters made of large particles.
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