A growth model for the generation of particle aggregates with tunable fractal dimension

A new 3D off-lattice model is proposed to generate porous and controlled fractal aggregate structures. The method is a variation of the Eden Model with the additional capability of randomly inactivating particles with a given inactivation probability. As this probability increases from 0 to 1, the proposed model follows a continuous transition from an off-lattice Eden Model leading to a core-dense random structure to a self-avoiding random walk model leading to a linear chain with partially constrained growth directions. The resulting aggregates have been characterized in terms of their radius of gyration, shape factor, mass and surface fractal dimensions, pore volume fraction, specific surface area and pore size distribution. A large range of microstructural properties can be controlled by adjusting the inactivation probability and the number of particles (e.g. mass fractal dimension from 1.6 to 3). In addition the proposed approach is convenient to implement and highly computationally efficient. The morphology (radius of gyration and mass fractal dimension) of silica aggregates characterized by small angle X-ray scattering in the literature was successfully reproduced to demonstrate the capabilities of the method.