Published online by Cambridge University Press: 10 February 2011
The hydrolysis and self- and cross-condensation kinetics of the hybrid sol tetraethoxysilane and ethyltriethoxysilane were investigated by high resolution 29 Si NMR spectroscopy. A kinetic model in which hydrolysis is reversible and condensation is irreversible was developed. We found excellent agreement between the product distributions measured by 29Si NMR spectroscopy and calculated by the model. The cross-condensation rates for each of the sols were intermediate to the condensation rates of the individual components. Calculations show that for these sols, the concentration of cross-condensed species is a weak function of the relative rates of self-condensation.
This work was supported by the United States Department of Energy under contract DE-AC04-94AL8500