Mixing Speed- and Temperature-Controlled Microreactor for Gold Nanoparticle Synthesis

In this study, we fabricated the microreactor which enables to control mixing speed and reaction temperature since their conditions are considered as essential parameters for chemical reduction method of gold nanoparticle synthesis. The microreactor consists of valveless micropumps and a microchannel for mixing and reaction. Mixing speed was controlled by the pulsed mixing method with two micropumps and reaction temperature was controlled by micro thin-film heater fabricated on the backside of a microchannel chip. Then, gold naoparticle was synthesized using the fabricated microreactor. The coefficient of variation decreased with increasing the mixing speed and the percentage of spherically-shaped particle increased with increasing the reaction temperature. Finally, the coefficient of variation of 15 % and the percentage of spherically-shaped particle of 100 % for the mean diameter of 65 nm were achieved.