Functionalization of nanoparticles to control physiochemical characteristics of the surface is the major challenge inhibiting transition of many nano-technologies, from optoelectronics to multifunctional composites, specialty coatings and electronics fabricated with nanoinks. The optimal interface reflects a complex interrelationship between NP surroundings and the architecture of the functional canopy, which to date has been unraveled sequentially and through slow conventional experiments. Herein, we address this challenge via Microfluidic Discovery Platform (MDP). MDP borrows from “lab-on-a-chip” concepts to enable precise, computer control of reagents addition, sequential reactions, complex inline characterization (UV-Vis, SAXS), purification and product-separation on a low cost, custom printed fluidic platform. To demonstrate the efficacy of the MDP design, we demonstrate facet-specific diazonium functionalization of plasmonic nanorods. Diazonium coupling to form strong Au-C bonds replaces conventional weak Au-S coupling to provide enhanced thermal stability for processing, as well as new avenues to manipulate optoelectronic and plasmonic properties. However, current attempts indicate that the reaction is highly sensitive to time, temperature and reagent addition, which challenges batch-to-batch quality. We optimize MDP via fluid modeling and prototype fabrication with additive manufacturing and integrate it with spectroscopy to demonstrate in-line reaction optimization. Our approach will provide a basis to develop versatile and optically active nanomaterials such as compositionally graded ligand or plate-ring architectures, that would be exceedingly difficult in flask-based chemistry.

Microfluidic discovery platform: Toward nanoparticle functionalization through closed loop optimization

253rd National Meeting (2017)

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