Keywords: microreactors, PDMS, polydimethylsiloxane, microfluidics, gold nanoparticles, silver nanoparticles, transmission electron microscopy, optical microscopy, nanoparticle synthesis, nanotechnology, microreactor synthesis, monodispersity
Room temperature, water-based, microreactor synthesis of gold and silver nanoparticles
Synthesis of gold and silver nanoparticles at room temperature using a polydimethylsiloxane (PDMS) microreactor has been reported. The reactions have been performed using aqueous metal salt solutions and borohydride reducing agent with tri-sodium citrate as the capping agent. Effect of concentration of reducing agent on the optical properties of the nanoparticles has been investigated. The nanoparticles were characterised by UV-Vis absorption spectroscopy and transmission electron microscopy. The UV-Vis absorption spectra show a blue shift in the spectra with increasing concentration of the reducing agent, which indicates reduction in the size with increased amount of the reducing agent. The sizes of the nanoparticles are uniformly smaller in the microreactor synthesis as compared to those in the conventional batch synthesis, under similar reaction conditions. The microreactor synthesis is very fast and improves the monodispersity with excellent reproducibility.