Investigation of the fractal properties of aerogels by diffusion-limited aggregation models

Abstract

Aerogels are highly porous materials characterized by low thermal conductivities and sound velocities. Most aerogels exhibit fractal morphology which strongly influences their mechanical properties. Diffusion-limited aggregation (DLA) and diffusion-limited cluster aggregation (DLCA) models [7] best describe the properties of silica aerogels [3, 6]. In our work, these models are implemented to characterize the fractal features and mechanical properties of silica aerogels. To this end, the model results are first validated by comparison with the fractal exponents derived from experimental small angle X-ray scattering (SAXS) data. Furthermore, the application of such aggregation models to describe the mechanical properties of these aerogels is studied by importing the generated structure into a finite element analysis (FEA) tool.