Crossover from reaction-limited aggregation to diffusion-limited aggregation of asphaltenes in hydrocarbon solutions

摘要

The nature of aggregation kinetics of colloidal asphaltene particles in mixtures of toluene and n-heptane has been investigated by dynamic light-scattering. As asphaltene solutions are almost opaque, an original optical scheme has been designed to perform light-scattering measurements in non-transparent fluids. Diffusion-limited and reaction-limited regimes of aggregation as well as a crossover between these two regimes have been observed. A universal scaled description of the observed phenomena is proposed.