Small gold nanoparticles formed by rapid photochemical flow-through synthesis using microfluid segment technique

  • Lars Hafermann
  • J. Michael Köhler
Research Paper


The photochemical synthesis of gold nanoparticles was transferred into a three-step micro-continuous flow process. A solution of tetrachloroaurate and a solution of a photoinitiator and polyvinylpyrrolidone were mixed within micro-fluid segments using a cross-injector. The segments (0.5 mm inner diameter) pass a focused UV ray after a short mixing by means of segment-internal convection. The nucleation of nanoparticles was initiated by this exposure, which lasted 30–300 ms depending on the applied flow rate. The growth of nanoparticles was completed by the passage of a residence loop of a length of 0.5 m. The obtained colloidal product solution was characterized by UV/VIS spectrophotometry, centrifugal sedimentation spectroscopy, dynamic light scattering, and SEM/TEM. In result, small gold nanoparticles with enhanced quality, compared to photochemical batch experiments, were obtained. The particle size can be tuned by variation of the composition of reactant solutions or flow rate between 2.5 and 4 nm. The small gold nanoparticles are suitable for use as seed particles for the formation of larger particles with an adjustable diameter.


Droplet-based microfluidics Fast nanoparticle nucleation Gold nanoparticles Micro-continuous flow Photochemistry 



The authors gratefully acknowledge the funding from BMBF (project “BactoCat” Kz: 031A161A). Furthermore, we thank Andrea Knauer for the helpful discussion and Steffen Schneider for the technical support.


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Copyright information

© Springer Science+Business Media Dordrecht 2015

Authors and Affiliations

  1. 1.Department for Physical Chemistry/Microreaction Technology, Faculty of Mathematics and Natural Science, Institute for Chemistry and BiotechnologyTechnische Universität IlmenauIlmenauGermany

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