Modeling and optimization of surface-methylated silica aerogel microsphere synthesis

Silica aerogel microspheres (SAMs) have attracted considerable interest for applications in catalysis and aerospace, yet the lack of systematic, quantitative design rules remains a major barrier to their scalable synthesis. Herein, we present a mechanism-based, multiscale modeling framework that quantitatively integrates predictive descriptions of each critical step in the synthesis of hydrophobic SAMs. First, droplet formation in microchannels was resolved using CFD-based Volume of Fluid (VOF) simulation, permitting accurate prediction and control of microsphere size via channel geometry and flow conditions (deviations <10%). The subsequent sol–gel transition and surface modification are described by a diffusion-controlled shrinking-core model, establishing explicit relationships between microsphere diameter and reaction time. Finally, classical nucleation theory (CNT) combined with molecular dynamics simulation identifies a critical temperature for cavitation-dominated solvent removal under ambient pressure, enabling the production of shrinkage-free aerogel microspheres. Compared with previous studies, this multiscale, mechanism-driven framework converts an optimized synthesis route into a predictable, engineerable process with clear advantages for scale-up and manufacturing.