RESUMO
The kinetic model of stepwise polymerization is revisited, with some adaptations for its application to the kinetics of oriented attachment of nanoparticles in colloidal suspensions, which results in the formation of anisotropic particles. A comparison with experimental data reported in the literature shows good agreement with the model and supports comparisons with other systems.
RESUMO
In this article, we report the formation of dispersed anisotropic nanostructures by the oriented attachment mechanism, under hydrothermal conditions and in a system that all other growth processes are improbable. The comparison of dilute and agglomerated experimental conditions indicate that oriented attachment is an effective mechanism for the formation of anisotropic nanocrystals, and the conclusions can be extended to other nanometric systems.
RESUMO
This work describes the synthesis, at room temperature, of doped and undoped SnO2 nanocrystals (particle size ranging from 1-3 nm) with no thermal or hydrothermal treatment. To the best of our knowledge, this is the first time that the synthesis, at room temperature, of doped and/or undoped SnO2 nanocrystals has been reported. This new synthesis method is based on the controlled oxidation, hydrolysis and polycondensation of tin ions in an ethanol solution. Another novel aspect of this method is the possibility of using surfactants, which may provide improved control over the particle size.