Electrically controlled mass transport into microfluidic droplets from nanodroplet carriers with application in controlled nanoparticle flow synthesis
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c8lc00114f.pdf
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Author(s)
Gu, Tonghan
Zheng, Cao
He, Fan
Zhang, Yunfei
Khan, Saif A
Hatton, Trevor Alan
Date Issued
March 2018
Journal
Lab on a Chip
Publisher
Royal Society of Chemistry (RSC)
Citation
Gu, Tonghan, Cao Zheng, Fan He, Yunfei Zhang, Saif A. Khan, and T. Alan Hatton. “Electrically Controlled Mass Transport into Microfluidic Droplets from Nanodroplet Carriers with Application in Controlled Nanoparticle Flow Synthesis.” Lab on a Chip 18, no. 9 (2018): 1330–1340.
Version
Final published version
Abstract
Microfluidic droplets have been applied extensively as reaction vessels in a wide variety of chemical and biological applications. Typically, once the droplets are formed in a flow channel, it is a challenge to add new chemicals to the droplets for subsequent reactions in applications involving multiple processing steps. Here, we present a novel and versatile method that employs a high strength alternating electrical field to tunably transfer chemicals into microfluidic droplets using nanodroplets as chemical carriers. We show that the use of both continuous and cyclic burst square wave signals enables extremely sensitive control over the total amount of chemical added and, equally importantly, the rate of addition of the chemical from the nanodroplet carriers to the microfluidic droplets. An a priori theoretical model was developed to model the mass transport process under the convection-controlled scenario and compared with experimental results. We demonstrate an application of this method in the controlled preparation of gold nanoparticles by reducing chloroauric acid pre-loaded in microfluidic droplets with l-ascorbic acid supplied from miniemulsion nanodroplets. Under different field strengths, l-ascorbic acid is supplied in controllable quantities and addition rates, rendering the particle size and size distribution tunable. Finally, this method also enables multistep synthesis by the stepwise supply of miniemulsions containing different chemical species. We highlight this with a first report of a three-step Au-Pd core-shell nanoparticle synthesis under continuous flow conditions.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
Massachusetts Institute of Technology. Department of Chemistry
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Creative Commons Attribution 3.0 Unported license
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DOI of Published Version
https://doi.org/10.1039/C8LC00114F
