Reactive Modelling

The ability to generate nanostructured materials with tailored morphology or chemistry is of great technological interest. One proven method of generating silicon-oxide materials is through the reactions of molecular building blocks known as alkoxysilanes. Alkoxysilanes are a class of chemicals which contain one or more organic alkoxy groups bonded with silicon atoms. Alkoxysilanes can undergo reactions to form siloxane bridges (Si-O-Si). Due to their ability to polycondense into materials, they have a number of interesting applications such as: the generation of synthetic porous materials through the sol-gel process. Despite the widespread study of sol-gel processes, it is difficult to predict the morphology of the final products due to the large number of process variables involved, such as precursor molecule structure, solvent effects, solution composition, temperature, and pH. To determine the influence of these variables on the products of sol-gel and coatings processes, we have performed molecular dynamics simulations using a reactive force field (ReaxFF). The cluster growth of alkoxysilanes in solution with methanol and water was revealed to occur by both monomer addition and cluster-cluster aggregation mechanisms. The morphology and local structure of trialkoxysilanes was observed in simulations for the first time, revealing a loosely bound network of siloxane sheets and silsesquioxane cages. Our simulations have given insight to experimentalists in the area

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