(683c) La Mer Burst Nucleation and Growth: Assumptions, Models, and Data

Recent efforts to synthesize monodispersed nanoparticles have employed in situ reactions to steadily and homogeneously generate a mounting solute supersaturation. As the supersaturation climbs past a critical level in solution, the nucleation rate spikes giving birth to a large population of nuclei over a very short interval of time. Subsequent growth of these nuclei lowers the supersaturation and thereby suppresses further nucleation. The result is a large population of nearly monodisperse particles. Classic experiments by T. Sugimoto and others have been modeled with deterministic models having separate stages of supersaturation build-up, nucleation, growth, and sometimes ripening. We examine assumptions in these models within the context of chalcogenide nanoparticle synthesis (Prof. J. S. Owen) and gold nanoparticle synthesis (Prof. S. L. Scott). We present a fully non-equilibrium stochastic model for LaMer burst nucleation with comparisons to results from simpler models. The results should clarify whether fit parameters from simple models accurately resolve the microscopic nucleation and growth kinetics.