In this work, we pioneer an autonomous, self-regulated manufacturing flow platform for the synthesis of targeted bi-metallic nanoparticles with dial-a-particle capabilities up to 100 nm sizes. We showcase the technology for monometallic (Ag) and bimetallic core-shell (Ag@Pt) nanoparticles to demonstrate its potential for the distributed manufacturing of materials on demand with minor human-intervention. This technological platform offers: (i) materials on-demand (wide range of sizes), (ii) distributed manufacturing, (iii) minor human-intervention, (iv) controllable multi-stage synthetic protocols, (v) real-time multi-point particle characterization (v) modular flexibility, and (vi) precision. The novelty of this work lies in the modular approach of the platform equipped with low-cost spectroscopy that enables fast (within a few seconds) monitoring at multiple points of the synthesis. Size tuneability is successfully achieved in the absence of organic capping ligands, using early growth information to mechanistically predict the resulting particle properties. We demonstrate that access to early-stage data in long synthetic routes (> 10 minutes) is vital to ensure a smooth and stable operation with minor user intervention. This work goes beyond the previous state-of-the-art of automated manufacturing approaches and rapid characterization [4], limited until now to single-step and rapid (~minute per iteration) syntheses [3]. It also advances our previous work on the continuous synthesis of seed-mediated growth of silver citrate-based nanoparticles with sizes ranging from 4 to 80 nm using multi-stage flow systems [5] where lack of automation leads to an off-target average inconsistency of ±13% (>100 syntheses). Indeed, herein, we demonstrate control not only within the variable reaction parameters (e.g. concentration, pH, time per stage, micromixing, etc) but also uncontrollable parameters that detrimentally affect the reproducibility and repeatability of the system such as precursor ageing, feedstock inconsistency, flow fluctuations, fouling, speciation, metal traces, etc. [2, 5].
As a result, this work will close the gap between nanomaterial research [1] and their near-future industrial deployment [2] opening the door to exciting opportunities for nanoparticles in a wide range of applications such as catalysis, energy materials, bio-medicine, and bio-imaging.
References:
[1] L. Liu, A. Corma, Chemical Reviews 2018, 118, 4981; U. Aslam, S. Chavez, S. Linic, Nature Nanotechnology 2017, 12, 1000; N. G. Bastús, F. Merkoçi, J. Piella, V. Puntes, Chemistry of Materials 2014, 26, 2836.
[2] Y. Gao, B. Pinho, L. Torrente-Murciano, Current Opinion in Chemical Engineering 2020, 29, 26.
[3] S. Li, R. W. Baker, I. Lignos, Z. Yang, S. Stavrakis, P. D. Howes, A. J. deMello, Molecular Systems Design & Engineering 2020; L. Bezinge, R. M. Maceiczyk, I. Lignos, M. V. Kovalenko, A. J. deMello, ACS Applied Materials & Interfaces 2018, 10, 18869.
[4] R. W. Epps, K. C. Felton, C. W. Coley, M. Abolhasani, Lab on a Chip 2017, 17, 4040; K. Abdel-Latif, R. W. Epps, C. B. Kerr, C. M. Papa, F. N. Castellano, M. Abolhasani, Advanced Functional Materials 2019, 29, 1900712; H. Bolze, P. Erfle, J. Riewe, H. Bunjes, A. Dietzel, T. P. Burg, Micromachines (Basel) 2019, 10, 179.
[5] B. Pinho, L. Torrente-Murciano, Reaction Chemistry & Engineering 2020, 5, 342.
[6] B. Pinho, L. Torrenteâ€Murciano, Advanced Energy Materials 2021, 11, 2100918.
