(653d) A Generalized Kinetic Model for the Growth of Single-Walled Metal Oxide Nanotubes

The synthesis of 1-D nanoscopic objects (such as nanotubes and nanowires) on a larger scale (e.g., kilogram or ton scales) is necessary for their technological application. A quantitative multiscale understanding of the growth of such objects via detailed growth models, is critical to be able to predict and control key parameters such as the length distribution and yield. Such a model can then be used to design liquid-phase reactors for scale-up of nanotube or nanowire synthesis. In this talk, we present a generalized kinetic model to describe the reactions leading to formation and growth of single-walled metal oxide nanotubes, together with detailed experimental data on the evolution of single-walled nanotube populations in a batch reactor. This model is capable of explaining the evolution of nanotube populations as a function of kinetic parameters. It also allows considerable insight into meso/microscale nanotube growth processes. For example, it shows that two different mechanisms operate during nanotube growth: (1) growth by precursor addition, and (2) by oriented attachment of nanotubes to each other.  Furthermore, the predictive capabilities of the model are illustrated by comparison of experimental and simulated nanotube length distributions during the synthesis. We conclude with a discussion on the use of such models in the design of reactors for production of nanotubes (and by corollary, nanowires) with complex structures.