Probing the Mechanism of Silica Polymerization at Ambient Temperatures using Monte Carlo Simulations

We have developed a model for silica polymerization at ambient temperatures and low densities and have studied this using reactive Monte Carlo simulations. The model focuses on SiO 4 coordination with the energetics of hydrolysis and condensation reactions treated via the reaction ensemble. The simplicity of the model makes large system sizes accessible on a modest computation budget, although it is necessary to make additional assumptions in order to use the reactive Monte Carlo method as a simulation of the system dynamics. Excellent agreement for the evolution of the Q n distribution is obtained upon comparing the simulation results to experimental observations. The analysis of simulation trajectories provides mechanistic insight into the polymerization process, showing the following three regimes: oligomerization (0−1 h), ring formation (1−2.6 h), and cluster aggregation (2.6−5.6 h).