With the use of a flow focusing microfluidic chip, micron sized hexane droplets were created within a continuous water phase. By varying the reaction conditions, a facile and rapid method was created for synthesising single crystal gold spherical and platelet particles several microns in size. The technique allows the number of droplets, their diameter and even the concentration of reactants in both phases can be controlled. Each droplet acts as microreactor for a reaction between decamethylferrocene, DmFc, within the hexane and Gold chloride, AuCl4-, within the aqueous phase. The reaction is spontaneous at room temperature, creating Au nanoparticles at the interface of the emulsion droplet, in contrast to the reaction at a large free standing interface, which produced smaller spherical gold nanoparticles, AuNPs. The size and shape of the AuNP is controlled by varying the concentration of the reactants and the size of the droplets themselves. By tuning the reaction parameters, the synthesised nanoparticles vary from being nanometre to micron in size spherical or platelets. The effects of the surfactant chosen to stabilise the droplets was also studied, and it was shown that whilst it influenced the particle shape, it was not the sole mechanism for forming nanosheets. Finally the additional of other nanoparticles within the droplet, allows for core@shell particles to be readily formed and we believe this could be a versatile platform for the large scale production of core@shell particles.
Suchanuch Sachdev, Rhushabh Maugi, Jack David Woolley, Caroline Ann Kirk, Zhaoxia Zhou, Steven D. R. Christie, and Mark Platt
Langmuir, Just Accepted Manuscript
Publication Date (Web): May 17, 2017
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