Mixing speed-controlled gold nanoparticle synthesis with pulsed mixing microfluidic system
- 580 Downloads
Gold nanoparticles with diameters of a few tens of nanometer and a narrow size distribution were synthesized using a pulsed mixing method with a microfluidic system which consists of a Y-shaped mixing microchannel and two piezoelectric valveless micropumps. This mixing method enables control of the mixing speed of gold salts and reducing agent by changing the switching frequency of the micropumps, which was our focus to improve the particle size distribution, which is an essential parameter in gold nanoparticle synthesis. In the proposed method, the mixing time was inversely proportional to the switching frequency and the minimum mixing time was 95 ms at a switching frequency of 200 Hz. During synthesis experiments, the mean diameter of the synthesized gold nanoparticles was found to increase, and the coefficient of variation of particle size was found to decrease with decreasing mixing time. We successfully improved the coefficient of variation to less than 10% for a mean diameter of around 40 nm.
KeywordsGold nanoparticle Mixing speed Pulsed mixing Microfluidic device Micropump
This work was conducted in Kyoto-Advanced Nanotechnology Network, and supported by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. This work was also supported by Grant-in-Aid for Young Scientists B (No.18710078). The authors are grateful to Sadamu Kinoshita for the SEM observations.
- Frens G (1973) Controlled nucleation for the regulation of the particle size in monodisperse gold suspensions. Nat Phys Sci 241:20–22Google Scholar
- Grigorenkol A, Geiml A, Gleesonl H, Zhangl Y, Firsov A, Khrushchev I, Petrovic J (2005) Nanofabricated media with negative permeability at visible frequencies. Nature 438:17–20Google Scholar
- Hayamizu S, Higashino K, Fujii Y, Sando Y and Yamamoto K (2002) New bi-directional valve-less silicon micro pump controlled by driving waveform. In 15th IEEE international conference on micro electro mechanical systems (MEMS 2002), pp 113–116Google Scholar
- Mafune F, Kohno J, Takeda Y, Kondow T, Sawada H (2001) Formation of gold nanoparticles by laser ablation in aqueous solution of surfactant. J Phys Chem 105:5114–5120Google Scholar
- Shibamoto K, Katayama K, Fujinami M, Sawada T (2001) Fundamental processes of surface enhanced Raman scattering detected with transient reflecting grating spectroscopy. Anal Sci 17:91–94Google Scholar
- Tanaka S, Ichihashi O, Sugano K, Tsuchiya T and Tabata O (2007) Analysis of valveless piezoelectric micropump using electrical equivalent circuit model. The 16th international conference on solid-state sensors, actuators and microsystems (Transducers 2007), pp 2183–2186Google Scholar
- Wagner J, Tshikhudo TR, Kohler JM (2008) Microfluidic generation of metal nanoparticles by borohydride reduction. Chem Eng J 135:S104–S109Google Scholar
- Weng C-H, Huang C-C, Yeh C-S, Lei H-Y, Lee G-B (2008) Synthesis of hexagonal gold nanoparticles using a microfluidic reaction system. J Micromech Microeng 18:035019Google Scholar