Fabrication of Gold Nanoparticle Using Pulsed Mixing Method with Valveless Micropumps

Small-dispersed gold nanoparticles were produced using a pulsed mixing method with a microfluidic device. This mixing method allowed to control mixing time of gold salts and reduction agent which is essential parameter for gold nanoparticle systhesis. The microfluidic device utilized was consisted of a Y-shaped microchannel connected to an expanded microchannel and two piezoelectric valveless micropumps. It was confirmed that diffusion time of pulsed mixing was 234 times faster than that of a laminar flow mixing with the same microchannel width of 150 μm. The fabricated gold nanoparticles with mixing frequency of 200 Hz had average diameter size of 23 nm and its standard deviation of 3.1 %. The produced partcile size was increased and its standard deviation was decreased with increasing the mixing frequency.