Continuous Flow Synthesis of Metal Nanoparticles

This Small Business Innovation Research Phase I project will develop a continuous flow manufacturing process for the production of high concentration solutions of unagglomerated plasmonic metal nanoparticles. Since the plasmonic nanoparticles must be unagglomerated, they must be fabricated at a low concentration under ultra-clean conditions. The batch-based methods currently employed produce only dilute solutions at high cost (> $10,000/gram). Here we propose a continuous flow fabrication system that will fabricate, concentrate, and purify plasmonic nanoparticles without introducing agglomeration. The proposed manufacturing process utilizes no organic solvents, has a minimal waste and disposal stream, and will result in a dramatic reduction in the cost of plasmonic materials. By utilizing the unique optical properties of gold and silver nanoparticles to enable near-real-time feedback on the size and shape of the produced particles, we will be able to modify the relevant system parameters for dynamic control of the end product. Additionally, flow reaction conditions that are difficult to achieve in batch mode will lead to improved nanomaterials with precisely-controlled and narrow size distributions, and uniform crystallinity and shape, leading to immediate application success. The broader impact/commercial potential of this project will be the development of a flow manufacturing system for fabricating, concentrating and purifying nanoparticles. This system will reduce the production cost of plasmonic nanoparticles by a factor of 100 versus current commercial pricing. Flow processing will allow for large quantities of nanomaterials with the same characteristics to be produced, providing a reproducible starting point for the manufacturing of other more complicated nanocomposite materials. Additionally, the highly controlled reaction conditions will yield plasmonic nanoparticles with larger scattering and absorption cross sections, narrower resonance peaks, and highly tunable peak extinctions across the visible and infrared regions of the spectrum. At the proposed cost point, new applications that require substantial quantities of metal nanoparticles will become commercially viable. Potential products include thermally enhanced fluids, adhesives, thermal interface materials, optical filters, photonics elements, obscurants, sensors, environmental tracers, antimicrobial surfaces and cosmetics.