Towards Sustainable Material Development: Computational Modelling of (Aero)-gels

Abstract

Amidst the escalating demand for environmentally friendly products, there's a concurrent push for the advancement of sustainable materials and their development methodologies. In response to such needs, materials synthesised via sol-gel processes, especially aerogels, have gained prominence due to their lightweight and porous nature. This attribute makes them highly versatile, finding applications in insulation, absorption, and as substrates for catalysts. Aerogels exhibit a complex, multi-level structural formation, which poses significant challenges for purely experimental analysis for reverse engineering. The diffusion- or reaction-limited cluster-cluster aggregation (DLCA/RLCA) computational approach has traditionally been the modelling method of choice for simulating the kinetics of particles undergoing Brownian motion and for tracking the structural and kinetic evolution during the formation process. Previous investigations employing this model primarily focused on the gelation phase and the resultant structural characteristics, overlooking the critical influence of the drying phase on the aerogel's microstructural properties. This research aims to enhance this computational model to more accurately depict the gelation phase while also incorporating simulations of the drying effect on the microstructure. Specifically, it employs finite element method (FEM) simulations to investigate the influence of supercritical drying on alcogel structures, with a particular emphasis on pore shrinkage. Although the study currently concentrates on silica aerogels, the model is designed with the potential to be extended to other types of particle-aggregated aerogels. By combining simulation results with experimental findings, this study seeks to validate the refined model and to determine the extent to which the model improvements accurately mirror the physical characteristics of actual materials.