(348i) A High-Throughput, Continuous-Flow, ‘Green' Process for the Synthesis of Metal Nanoparticles

Size and shape controlled metal nanoparticles and their assemblies find applications in various fields such as plasmonics, disease prevention and control, electronics and catalysis. Commercialization of such applications calls for low-cost production of nanoparticles in bulk quantities that entails continuous flow processing. Liquid-phase, room-temperature, redox reactions are compelling routes for continuous nanoparticle production, on account of their reduced energy demands. The reactivity of precursors used in nanoparticle synthesis is quite high; so, nucleation and subsequent growth of nanoparticles occurs rapidly (~ ms) and could lead to polydisperse nanoparticles, if the mixing is performed uncontrollably. Here we report on the development of a rapid, green, batch protocol for metal nanoparticle synthesis in minutes, and the design of a novel thin-film reactor for scaling-up of this batch protocol into a high-throughput, continuous-flow process. The novel reactor design reproducibly generates micron-scale segregation length scales upon initial contact of the two precursors with the aid of centrifugal forces, thereby eliminating the need for high pumping forces required in microchannel reactors. The novel reactor was used to synthesize monodisperse gold nanoparticles (5 ± 1.2 nm) at a processing rate of 5 mL/s (~ 100 mg/min of gold). The effect of various operating parameters on the synthesis of metal nanoparticles will be presented.